Pragmatic 46: Out of Steam About Steam

20 November, 2014

CURRENT

We delve into energy conversion efficiencies of solar photovoltaics, fuel cells, the Hydrogen Economy, steam and hydro-turbines and ways you can conserve energy in your home.
Transcript available
Welcome to pragmatic pragmatic as a weekly discussion show concertina practical application technology exploring real-world trade-offs we look at our great ideas are transformed into products and services that can change our lives nothing is as simple as it seems this episode is sponsored by igloo new sponsor and intranet you'll actually like built with easy-to-use apps like filesharing blogs calendars task management and lots more visit igloo software or one word.com/pragmatic to get started today it's free to use for up to 10 people this episode is also sponsored by Lynda.com Lynda.com is the easy and affordable way to learn we can instantly stream thousands of courses created by experts in their fields of business software web development graphic design and lots more visit LY NDA.com/pragmatic to get a free seven-day trial if you ever want to learn something new what are you waiting for little more about them during a show on your host John Geagea and I'm joined once again today by my co-host Vic Hudson has gone back it is good John as a Grand Prix of is going very well so just quickly as possible to see a list of topics are becoming a show coming weeks and take distortion.com/topics and also started to release an equivalent to the after dark at our farm is like/B-sides/no doesn't fit into the show thing and calling addenda it's a take distortion.com/podcasts/addenda go check it out was a nice sorry I should say this episode because it mainly nighttime when you're actually listening to this episode so I apologise for the presumption that it's coming item you're listening to it and mean up in a family recording indeed if you're on your part of the little ball that we live on so yes ashes of such a little ball anyway this particular topic was our suggested by our client I now pronounce the name before and I got it right so the pressure is on me to remember how I pronounce that arm Latin, Latin and are suggesting 9 October Cisco and backyard a few weeks now and it was them highest voted topic in the list so read out the whole topic suggestion and will go and I should say what we recover and were not okay so the full-time of the full topic is efficiency of various energy production methodologies such as nuclear gas coal solar wind et cetera finding ways to reduce energy usage and debating the path to cleaner energy so the problem with this topic and I mean I say the problem with this topic I don't mean a detrimental way but loses the fact is that Ivory talked about some of the stuff previously on episode to the battery problem and the thing about the battery problem is that it is kind of fan favourite episode of pragmatically so far anyway here we are episode 46 it's the fan favourite insofar as it had the most feedback of any episode that I've made more than coffee although copies had the most downloads are over say the Barry problems had more feedback and more requests arm for more information so and is reflected by the figures we had for follow-up sites so I did stop and think what I got this topic suggestion when I simply do part E to the for the battery problem but I decided not to I think will do this as a standalone episode God reliant some point so arm crisis and of when he made a suggestion I will break this into two pieces and is I guess I can start by recommending if you haven't listened episode to go back and listen to it are and all the follow-up episodes are there is a lot in them so what I do, focus specifically on efficiency so will talk specifically about efficiency of different generation technologies as an energy generation although technically I guess its electricity generation and its energy conversion so energy conversion being different from you because you can't create energy so the other piece on the look into it and look into the environmentally friendly approach is that you can take the Neo again like the namesake and show the pragmatic approach as you can take to improve energy efficiency in your house so those the two paths I want to explore and mainly because a lot of the other stuff in that in that topic has already been covered we think sounds good going on I do also on the next hour 10 or so is be doing a few more topics are like it that is sort of along those lines but going into a lot more detail but keep an on site you'll your ceremonies things, is an excellent resource for information the subject it's called electro-PR Electra PDR there is a link in the show notes highly recommend checking it out it has a absolute hunt of information about energy efficiency different technologies it really is a great resource okay so let's talk about this conversion of energy not cost effectiveness those big be clear of running my diet or better cost effectiveness of it I don't talk about reliability of supply and I will talk about maintenance costs we just gonna focus on efficiency now the problem is the efficiency of the converter exactly the problem is if you would look at the efficiency of the conversion of all the different technologies you would see hydroelectricity at the top of the list and you would see PV cells in our photovoltaic cells solar cells in see them almost at the bottom and you might start thinking well if we just install hydro everywhere and throwing us away would be fine right obviously that's not the whole story hydro plants are enormous you have to drown massive areas of the countryside to build efficient decent sized hydroelectric plants and the fact that you can put a solar panel on your roof pretty much anywhere you like in the world are without impacting anything well you know obviously that's a big difference a big deal you can't ignore that kind of flexibility I'll you and it's a heck of a lot cheaper so it's not the whole story still definitely worth looking at the different efficiencies and the different trade-offs so I think it is interesting yes I think it is worth diving into outer life we picked this topic but ultimately the pragmatic silt solution to our energy problems is not just about efficiency has to be balanced with cost feasibility environmental impacts all that stuff right now about that so I will break it down into the three are specific values that are often quoted the first and often quoted one is the theoretical limit so the theoretical efficiency limit are then I want all bouts are the presents are little laboratory bests or the land best to the best they can do in a controlled environment and then finally where we are carried out with the mass produced are efficiencies of these different technologies in other words right now I can mass-produce 100 generators they are the best one you're looking at a mass-produce favour about this so that's the realistic right now with current technology is what we can create so when I speak theoretical I guess I'm I'm talking about in materials and technologies that don't necessarily currently exist we assume someday that they could exist but and then maybe we be out of reach that theoretical limit but you theoretical limit means the recognising right now not possible size be clear about that upfront and whisper as far as laboratory goes that ignores our physical capability to actually manufacture these things en masse where that's solar cells of its fuel cells whether or not it's a hydro plant in a narrow there are limitations to how big we can make machines like my gay internal combustion engines draw will get to is there is a physical limitation that you start reaching me try mass-produce these things not everything scales and a good example of this is nuclear fission the other week week we can we know that equals MC squared we know you smashed your deuterium entry and you will you will get a helium and you get a heck of a lot of energy can we know that we can do that laboratory environment for a short period of time have we got any nuclear fission power stations that actually work in the world yet and the answer is no that it thinks are no I mean they have them but they don't produce more energy than they consume in order to start the reaction yet so they do exist so scalable watch yet exactly the theoretical reactors not one on what that's that's really the wrong word their experimental reactors so they do exist but I don't actually generate a positive net surplus of energy at least not consistently so I can for sure. Timing shutdown so really night useful okay so what is efficiency wearing Vic was think it's a way to measure that the return versus investment of something yet exactly are and to put it in just using the word energy is energy out divided by energy in so energy can be in any lots of different forms anything that burns in a typically has to do with chemical energy the reaction of a compound whatever it might be with oxygen releasing he is a byproduct Neo and we use the heat usually to turn water into steam and then his esteemed drive bunch fan blades and a turbine and that in turn turns a generator several examples it with coal yard we burn a boiler so we crush up: your fine dust burn it and that you are in a boiler that heats up water going through pipes and a boil that makes steam them his esteemed drive turbine solar thermal all that infrared heat energy from sunlight is concentrating on molten salt and that makes steam and then that steam drives turbine now even with nuclear energy you know you equals MC squared alight we are we split we split some uranium some plutonium it's a break spa generates a whole bunch heat hopefully we leave enough control rods in their sodas and doing crazy and that the heat generate steam and steam drives turbine geothermal same carnitine drill hole in the ground down on pocket what you do pump water down that wall were making steam steam drive turbine seem common theme here many people have said that the steam engine is the largest generator of electricity in the world because technically it really is because all the technologies we hang off the end of them whether or not its nuclear fuel efficient nuclear fusion not yet fusion nuclear fission are well not its coal-fired websites gas-fired all of these things they all essentially generate steam to drive a steam to pretty much however there are of course different ways of driving the generator and you can actually directly mechanically drive the generator with for example an internal combustion engine so when taking chemical energy with physically forcing our than it to turn around walking improve internal combustion engines reciprocating I guess for the rotary engine and it generates road reaction but the point is that it physically spends a shaft and there is no steam involved then hydroelectricity falls in the same category we haven't no matter propel or set of propellers you the water pressure for is the return that directly drives generators that that will while call them near direct mechanically driven but you once your energy is sort of rotational then you get all the losses that come along with that but it's pretty consistent across all the different technologies once you reach that shaft all the efficiencies between 9599% pretty high pre-see once you reach that point there so the only losses you really get our resistive losses in the windings which is kind of obvious and and also obvious as the friction because your listing turns around your gravity acting on it you therefore where it's going to experience friction bearings and so on and so forth so are and that resist resistive airings than in maintaining our exactly moving parts right so that's all of the than those the energy arm different kinds of energy conversion generation technologies will touch on except for two more specials and these are ones that don't actually turn a single thing so their special solar note mice assigning photovoltaic solar and fuel cells and their unique insofar as they convert either photonic energy or electrochemical energy directly into electrical energy without turning anything mechanical and that has all sorts of other benefits not just from you that the efficiency point of view because you may say okay well they don't have that you that one of the 90 599% efficiency that you that you're losing in spinning up a generator generate electricity through magnetic fields retaining ankles and all my stuff know yet whatever that site is perfect but that's actually not true because you still have to go through because are those technologies will generate direct current sociology got devices rely on ACLU transmission lines are transformers that require a see you have to go through a decent A/C converter you loose and they collaborate so it's not perfect either so we can do is when I cut that out and we can ignore that we are saving a I'm only interested in the conversion efficiencies up to the point from spinning my shaft at that point in time it's a level playing field means not exactly but it's close enough because the efficiencies you get out of your AC/DC A/C AC/DC DCD CAC whatever convert accommodation you like you are still going to get some 2090 599% efficiency out of that converter just as you get around our back on a conversion efficiency out of your actual electrical generator fair enough for more things are going nor going or transmission losses we can ignore installation requirements and is mainly because I think they're relevant to the discussion and before we get stuck into the very first one I just need to quickly touch on the basis of this of Connor mentioned that the law of conservation of energy states that the total energy in an isolated system cannot change it can only be converted between different forms of energy so there are no local ain't no perpetual motion machine in this house done exist so you think you make a better motion using just forget it alrighty let's dance with the internal combustion engine showing what you reckon are right so insomuch engines is celebrated into two pieces gasoline and diesel and gasoline is typically modelled on something they call the Otto cycle but in an ideal scenario you can simplify that to the Carnot cycle is 100 formulas together are links on the show notes if your interest in what all that stuff means go right ahead but to carry on with that if you use ideal gases and you simplified to a Carnot cycle you get about 46% efficiency and that's your theoretical limit however engine components have mass movements causes friction inertia et cetera because it's reciprocating in the case reciprocating piston engines so it's I said that that is the theoretical limit that is using ideal materials real-world theoretical limit for gasoline engines around a 37% as a result of all the real world their implications is a very well understood problem as Intel machines and around 420 years or longer in a while all that lost energy thing yourself okay I'm burning my gasoline where is it going well it's going up and it's going as heat because you want the engine to self-destruct and melt therefore what you do you extract the heat had to do that in a pump cooling water through the engine and why indicators not air cooled but then most according just tender breakdown was certainly in warmer climes like I live in anyway so so much for your vee dub's in the 60s and the Beatles and so on is keep those key break in our climate there anyway are so you got your all energy is lost as heat and of course arson that he goes out hot gas and exhaust so he there's heat there's obviously vibration because you these these engines will vibrate a lot there on shock mounts to absorb the vibration of our vibration is vibrational energy that is lost energy and of course noise vibration drives no sound waves and the sound waves are that energy is also transmitted that way so you lose energy and all those different ways that now there's a great link on the physics stack exchange that I put on a show notes the goes into a fair bit of detail about the maths behind internal combustion engine efficiency for gasoline and diesel cycles different because of the way in which diesel side diesel is now combusted with our spark plug in high compression ratios and blah blah it can achieve a higher efficiency about 56% year and that's one of the reason with high compression diesel as were the reasons is becoming so popular more than half of the car sold in Europe and now diesel you know it's becoming very popular so the largest and most efficient for its size engine into must engine the world is a diesel engine it gets about 50% efficiency and is a marine engine is a marine engine I mean it's meant for a boat so the largest diesel generator in the world is 80 MW and at that point they tend stop now you may recall if you listen episode to arm then you will recall that I work to the sternal power stations to recap our it's a coal-fired power station with four arm fall for generator units for Teva general units and each one is three and 50 MW at 1.44 GW reasonable size plant and arm selling remarkable toothbrushes 80 MW is nothing compared to that in 80 MW is a fraction of a generator IRA now wanted one of the turbo generate turbine generators at centre now this way this route the reason for that is because you as you physically make the internal combustion engine bigger and bigger a lot of the physics doesn't scale because the piston simply get too big and they have too much inertia unable to much loss it becomes inefficient so internal combustion engines the whole idea of using a power generation a massive scale for the part they great for backup generators are great for isolated grids that are not huge like well a boat or a remote rural town that's it now before we start will talk about hydroelectric power next before we do that I like to talk about our first sponsor for the show and that igloo software new sponsor in engineering I've worked in a lot of companies that use mismatched collection of different tools to provide the basic functionality that you need to get your job done things like filesharing wikis announcement pages department landing pages there disconnected disorganised and for whatever reason they are never seen to work on an explorer seven and on your company provide desktop good luck used anywhere else that it was an intranet you'll actually like yeah they bring the ease-of-use from consumer 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igloo once you're in there it's surprisingly easy to start reorganising just the way you like it to fit your needs now thanks the built-in responsive design work on any device you could choose like a laptop tablet phone at all the major browsers in an explorer eight and up crime Firefox Safari and on iOS and android's native browsers well they also have dedicated apps for iOS android and blackberry datafile soap and a couple the things that that I played with specifically are manifold igloo it can be easily shared and seen by others within your igloo if someone wants to edit the file you can reserve and downloaded major edits then upload it when you done if you change your mind is release the lock all done through the browser there's a version control is done automatically you can add version change information each time beyond that you can associate tasks with the document refine other remind others that they need to review it or make comments and lots more it's home are much nicer than SharePoint now if you're not ready to abandon SharePoint yet that's fine with igloo you can use SharePoint archive your documents but you can collaborate within igloo and I were you leveraged both so that's few users but what if you're in charge of the IT side while ego handles a security hosting imaginal for you their data centre partner is SS a 16 certify they offer SSL encryption are ends when disaster recovery single tenant and shared environments integration with many authentication sync systems including sample services and LDAP now mid to late last year that was a 2013 I was working for a small start-up company called Project facilitation and based on my own experiences trialling igloo myself privately arm which we use it for building an Internet it was really handy and save us from having to develop and train integrated pieces that we need ourselves adding and moving around features many was really easy and what you see is what you get made so some of Jesus to tailor the way one without having to have any develop skills with a minimal learning curve we are happy with we would love very fast now you may have heard people talking about igloo in the past but take me I've used it is worth your time to check it out so how can you check it out it's easy just visit igloo software all one word.com/pragmatic specifically that URL and sign up for a trial it's free for groups of up to 10 people is no credit card required no obligation to sign up and have a play today I say have a play because it's so nice and fieldwork are I like to thank igloo for sponsoring pragmatic hydroelectric power everyone was hydro something the water do you like hydropower Vic sure please impeach this don't go swimming at the bird at the other dam wall okay the dam wall illegal fishing area they know as witnessed by Bob Simpson speaking indeed rights so for efficiency reasons and because the design of the different kinds of propels at all as you talk about arm you typically will drive the fan blades are a much lower speed than you would run a steam turbine so normally electric motor was run several thousand rpm behind a generator it's geared up from a very low physical RPM to a low running shaft speed so singles machine equation is for all those people are Donna would love to know is NS equals 120 Afon P where NS is a synchronous speed of the machine are F is the frequency and P is the number of polls and the scary thing is another look that up in a moment by increasing the number of polls you can reduce the speed the generator needs to spin and produce the same output frequency rights I want to cover how you want electric motors because no one cares arm but if you walk if you email me if you care and I'm happy to talk about the right say less than 5 MW ice plants they can achieve between 80 a 5% efficiency larger hydro plants will top out at about 95% conversion efficiency which is really good but the energy conversion you is high but in order to be economical it needs to be a larger scale and that's where hydro falls apart now I'm not including title or wipeout options I discussed that in part a follow-up episode two there's essentially two kinds of hydropower that I want to talk about these run of the so-called run of river and of course the obvious one very talk about is the dam to run a river is designed essentially to be on it to be partially immersed propellers they usually use and Calder Pelton turbine figure we'll with a bunch of scoops around their very it's it's kinda like a modern equivalent of a waterwheel and it's common for shallow fast flowing rivers and the idea is that a the plant will run at the speed that the river runs hence the name run of river really not that imaginative actually come to think of it now dams on the other hand and I guess some deeper and slower flowing rivers they may use a like a Francis reaction or a propeller or Kaplan turbine and there is less machine interview and more about each of those individually and how they're different but they all tend to rely on high head pressures to turn them and they turn their use the dam to generate that pressure yet they use the water had pressure which absorb and second so that in a much slower rotational rates and a Pelton does art but they produce much more talk and you can then gear that talk up to drive a generator even then it still spends a much slower shaft speed now I mention had pressure for those that don't know what had pressure is had pressure is the pressure created by a volume of water acting at a given point in a closed system so imagine your hose it says 10 feet long that's 3 m long and it's perfectly vertical you okay I know it a hydraulics on the lexical engineer whatever if I pressed my thumb over the bottom end of the hose that I thought the host the top of water there will be 10 feet or 3 m ahead pressure being applied to my thumb trying to seal off the bottom because the water isn't moving that's referred to as static had pressure if the water begins to flow as affected by the diameter pipe the tube and we start our Bernoulli equations flow dynamics and I drift off to sleep so really don't care anyway bottom line is that's what had pressure is so you have big dam you've got hundred metres ahead pressure behind it which is what I like to have a big dam wall and a big dam wall and near no-no makes a joke anyway and is that the height of the top of the water down to the lowest part of the dam was usually where they will place are the actual are propeller that drives the generators that I'll be at the bottom sometimes 11 run down the side of the health of old they will dam at the top of the hill in the run up a series of pipes right down to the bottom are as close the bottom as possible before they actually go through and start generating flow through the through the propellers and the reason I did as they were maximised ahead pressure yet more pressure more efficient obviously that's a problem you know if you've got Nero up a large area of land that is mostly flat and is bounded by bunch mountain ranges new you plug up the exits that's well and good but is that enough to make hydroelectric power station and the answer is usually no you need the height you need to head pressure so it's not just as easy as building a dam anyway so are that's hydro hydro sounds awesome until you have to flood everything again talked about a lot more about the other aspect of hydro and episode to Gable is that you want to know more about the other consequence of hydrant on covered again I guess I saw as steam engines and turbines so steam engines have two basic types there is an empty impulse type and the reaction time now there's our oligomer show notes to a site that has a very good discussion about steam engines and steam turbines I am going to read from that I've I've I've copied what they've got for the next two bits about the way that they work but I've tweaked the wording slightly are it just said it better than I thought I didn't see the reason reinvents these two things so this is the R visualises as best you can basin the words because I have no images to show that the steam jets are directed sizes are so this is a an impulse turbine steam jets are directed at the turbines bucket shaped rotor blades where the pressure exerted by the Jets causes the rotor to rotate and the velocity of the steam to reduce as it imparts its kinetic energy to those blades the blades in turn change the direction of flow of the steam however it's pressure remains constant as it passes through the rotor blades since the cross-section of the chamber between the blades is consists is constant impulse turbines are therefore also referred to as constant pressure turbines the next series of fixed blades reverses the direction also are also known as sorry reverses the direction steam before it passes the second row of moving blades and so Saturn impulse turbine a reaction turbine is when the rotor blades of the reaction turbine is shaped more like aerofoils and arranged such that the cross-section of the chambers formed between the fixed blades diminishes from the inlet side towards the exhaust CID blades the chambers between the rotor blades essentially form nozzles so that as the steam progresses through the chambers its velocity increases while at the same time the pressure decreases just as in the nozzles formed by fixed blades would do thus pressure decreases in both the fixed and moving blades as the steam emerges in a jet from between the rotor blades it creates a reactive force in the blades which in turn creates a turning moment on the turbine rotor so you can think of that as essentially it reacts to varying levels of pressure from the steam being forced over the blades as an aerofoil like an aircraft wing so you get a high-pressure one side lower pressure on the other side of it and though those reactions will cause it to move which is are the kind of turbines that they use acts asked in a power station for example okay hopefully people are still with me there anyway eventually the steam will reach such a low pressure when it is done that it can no longer perform any work so it still has heat and is not a liquid still steam problem is then you need to condense it back into water because you can't pump steam and vinegar pump water back into the boiler or whatever heating device you're using to go for another cycle now the condensing of the steam also has the effect of creating a not perfect but a partial vacuum and that partial vacuum creates a low-pressure zone which draws steam through the turbine which of course therefore further drives the rotation of the turbine by creating an extra low-pressure zone at the end Gattaca in a particular cycle they call that a rank and cycle and it's been around for quite a while the biggest problem with the rank and cycle and frankly me a lolly steam engines is at the condensing function represents a significant loss of energy so that's a problem so steam engines the problem I've got is looking for figures on efficiencies of steam engines it's difficult to get accurate figures because I looked and I looked and I look to get the exact figures and every time I found exact figures I found contradicting figures that there would be a lot of local variables sterner render that equation any redraft yet there are a lot of variables and that is a big simplification for you to simply say your eyes about 30% is 50% the RSI are you okay that's up to a certain flow rate a certain amount pressure you know the design of the blades and everything is so are well okay and Saigon through this list was the efficiency while it varies from 30% to 60% that's a horrible answer but I'm sorry that's all I could come up with because there's so much variability of steam engines it's so hard to be sure and so down to the manufacturing details than the specific conditions the problem also got to consider is that that's just the efficiency of the actual steam turbine part of it and I read some plaza say ITS 95% efficient and cycle actually know it's not because not including the condenser in your efficiency era so if you're a true rank and cycle would never achieve that new law of thermodynamics is gonna stop you anyway so the open dear me so steam when you consider steam plus the condensing plus the other boiling all that stuff like a coal-fired power station is horrendously inefficient end to end in a fit efficiencies are somewhere between 30 to 40% overall it's really terrible but because it's so cheap people don't care except the fact because the public tons of carbon dioxide in the atmosphere were there is that here bad naughty all right so I'm done talk about steam reciprocating engines are Mulberry talk about nuclear power and how that works previously well briefly and misery much else to say about it arm around Steve's arm as steam about steam brewing are my God could reserve sorry that's fine so let's talk about soul are as I love solar only solar is magical and awesome night covers in detail episode to listen more to say about essentially they are the way solar works at essentially it's it's doped silicon and the doped silicon type of our photovoltaic cell P conversion efficiency are at a specific wavelength by depending on how it's been doped with different chemicals now I carefully manufacturing transparent partly transparent layers and using different prisms and soul between layers it's possible to actually have multiple layers and you can build up a wafer that has different doped layers of silicon so instead of having a single wavelength so we can stack multiple layers to get to anyone three different are junctions so are each layer will convert a different wavelength so sunlight that we get is actually consist multiple wavelengths of light they will blend together gives white light in our eyes are see middle of the sun will have you looked really directly as sons generally considered bad days that the retina being my arm point is that all those different wavelengths you can then push your efficiency so when you are actually looking at the Shockley crease lower limits that in 1961 I figured this out I said look at maximum conversion you get from a PN junction is 33% extra single junction but that all assumes a single layer and a single predominant wavelength now you start stacking these things obviously you can absorb more energy you can capture more of the energy say rather it is been wasted now that then leads to a theoretical limit of between 85 and 90% of that importantly that assumes like concentration and belie concentration I'm referring to our solar concentrators like parabolic dishes mirrors refractors whatever you're taking large amount of sunlight falling over a larger area concentrating it down onto a solar cell and a much smaller area in other words you cheating mass okay I guess but if you put that on your roof realistically that's in a double triple quadruple the surface area on your roof you required to actually have like concentration to cotenant the solar cells in the mammal mail reach a point when I get leg and a home solar concentrator kit that they figure out some way of doing that nicely and neatly that's maintenance free and doesn't require cleaning in the and still then let's just run with the non-light concentrated maximum theoretical efficiency of 68% conversion so that's assuming you can capture all three like three layers witches were roughly where your efficiency trade-off drops off well actually I think he steps and is assuming an infinite number but you get very close to 68% with just three theoretically so anyway let's compare and contrast that theoretical limit with the best laboratory result at the moment and as Alina shown such as a night nice thing nice chart shows all the different lab results are by EPL and there was at part linked to it in my presentation and I did when I was working at a pre-previous company where I was giving a young architect talk are regarding solo solar electric design and that was Lincoln episode to so go and have a look about you really want something shows this one and it shows you all the different laboratory results up until a few years ago best results so far at that point in time of that chart being generated was 41.6% that was for a try junction to terminal monolithic 41.6 so that's not too far away from 68% I guess it's much more than halfway and something anyway now we bring you back down to earth how much is the efficiency of a mass produced current market solar cell what's your best guess spec are less they heard and that there are very good leg maybe 10 or 15% some collector boom spot on 15% so that your average usual production cell efficiency I say usual in a section 1 balance among the exact figure is 15.4% less knockabout point for so ultimately that's terrible yet but because it's cheap to make you can plus them anyway got a flat surface or an area that gets sunlight that changes things you know unlike hydro which requires huge amounts of land it needs to be high up in order for it to be efficient ago and because one of the best parts of solar is that there is no further loss that it's just directly converted DC Wego no mechanical conversion necessary rights next thing to talk about is fuel cells now I only fuel cells are a very cool technology but I have my doubts about this a lot of aspects so I want this focus is also the difference yourselves is a focus on hydrogen fuel cells because of the most commonly used discussed are prevalent okay so the concept works like this anode and cathode bits of yourself, like a battery cell and a cathode right the anode reacts with hydrogen and strips the electron from the proton because hydrogen is 011H right so one proton electron so the anode reacts about and strips off your electron the proton is capable of passing through the membrane but the electron isn't so as the proton passes out the other side the electron takes as it were the long way around to catch up as it passes out the other side and that creates an electrical current that is really simplified that the gist of it at the cathode that hydrogen then re-combines it combines oxygen and that creates water as a byproduct South super clean right sounds that sounds like it doesn't I'm guessing you tell me if there well the answer is it depends and will get to wine it so the electron as it split goes around creates about .7 V potential difference in the on hydrogen fuel cell say stack amongst those in series get bigger voltages and away go ride your EDC go on happily enjoying Roger's injury you'll enjoy your electrons okay so Key points needs oxygen to work but that's okay internal combustion engines do to the site so that they generate heat guess what those internal combustion engine no problem there are enough now for portable applications they use are safer and lighter polymer membrane but the problem the polar membranes not as efficient 50 to 60% conversion efficiency respectable admittedly but you know not not not not as good as hydro there is nothing to largerscale plants however ones are typically don't move values molten carbonate or solid oxide membranes and they can also then Eunice the head that they can also harness the heat that is generated by the fuel cell are an outstanding traffic referred as a combined cycle so you using the electrical energy plus the heat the waste heat generate out independently through more traditional means and essentially get a combined cycle efficiency of about 85% and that sounds really good however they are expensive to manufacture and most importantly any hydrogen is the fuel so how do you mass-produce your hydrogen hydrogen is one of the most plentiful elements in the universe plenty hydrogen game that's great but mass-producing hydrogen on earth at the moment it's actually done from something called steam reforming and that steam reforming is from natural gas natural gas is of course hydrocarbon that you get out of the ground like oil like coal so you get you can discount the natural gas surgery using the new generate greater struggle you're creating greenhouse gases as a byproduct of yellow reforming this disturbing steam reforming the natural gas you're creating greenhouse gas greenhouse gases a byproduct less really environmental friendly is it but that's how the majority of hydrogen is mass produced right now today that doesn't mean that's the way has to be that as the waiters at the moment that process takes a lot of energy and I guess the other thing is a psychoanalyst of the clean way when using electrolysis now controls a simple enough you pass a lovely pass on the actual current into a anode and a cathode into water and you will get hydrogen collecting around one and you oxygen collecting around the other you're splitting it by direct electrolysis but there is a problem that electrolysis it requires electricity which you go to get from somewhere else actually and it has a conversion efficiency that is not perfect so what you're essentially doing is you're taking electricity generated from somehow through some means to split hydrogen and oxygen once you've split that's not enough that hydrogen has to be carried around Enoch and I carried around in a balloon and talk funny when you breathe it maybe maybe you are but you know you can't put that in a car and go any distance it needs to be death pressed into are either highly compressed form of the gas or it needs to be compressed ideally down into a liquid liquid hydrogen you just like we do with allergy liquid natural gas LNG as its code available in that state is volatile in any state boats hydrogen is nowhere near as reactive as people like to think everything's Hindenburg is actually not is not might not as dangerous as you might think but even so there has that stigma that doesn't help its cause LNG is just as reactive anyway back in some respects allergy is more reactive so I am adamant that the point is that you have to now compression hydrogen and then your shipment around the all those processes take energy where is the energy coming from before you even get to generating electricity out of yourself and remember energy can't be created it can only be converted so winter and every step of the conversion you lose energy you lose energy in some form or another so what's happening is hydrogen is not a method of general of of creating energy from something that already exists like you if you're burning a hydrocarbon that energy was absorbed by the sun by plants in the earth in you cook in a way out for thousands and thousands of years that energy that's that's bottled up and you're burning it and that releases the energy that you then used to create work yes sunlight is liable energy from the sun right now and your conversion and electrical energy ball fuel cell is doing is taking hydrogen that you've collected and for collecting it through a clean means like electrolysis or you doing really is you're not actually releasing energy at all or you doing is returning the hydrogen that you split from the water back to water again and you're converting it back again and I conversion you are able to extract our justly from so in essence the hydrogen is storing the energy is like a battery so hence the term fuel cell exactly so it's not like any of the other technologies you know it is not so it's kind of I find this whole thing about evidences of hydrogen economy no anagram hydrogen fuel cell vehicles and the great body in his thing you gotta make the hydrogen somehow so what's that the ideal plan may be the ideal plan is you put hydropower every place you possibly can you put solar panels and everywhere else and is you do pump hydro storage for your storing your off your your peak energy seeking use during the night hydropower runs 24 seven and everyone's all happy that your electricity and then use that to create hydrogen use the energy from that to compress it and then you transported by truck to you service stations where people can then fuel up their cars of hydrogen and then fuel cells in the vehicle turn hydrogen into electricity which then drives the electromotive which then drives the vehicle or just a bunch of batteries and a car charger might like Tassell does and cut hydrogen out of the equation there which is simpler so the thing is I find the whole hydrogen economy idea to be somewhat flawed I don't see it as being any better or any worse than using batteries in many ways it's worse because L electrons that are carried over powerlines by those Tassell recharges supercharger stations right they take solar power and they buffer it against the grid you drive it new details are up electric vehicle up blob and to charge into the batteries drive a car away again all of that power has been either taken from the sunlight directly which has no wise or has come from wires that are already existing going to power stations already exist or hydro plants that may exist is using existing infrastructure with hydrogen there is no existing infrastructure something you have to build anything yet you got you've gotta have heightened that the botanical safety requirements of hot liquid hydrogen storage are more strict than for LNG you can't just use an LNG tank completely as it is you have to modify in some cases depending upon the standard you may have to replace it completely to support liquid hydrogen yellow so NSF 20 petrol stations out there that don't have LNG me and I live there I know I can be of several of my head and allergies been around for 25 years at least the first cars locally right live anyway so where does that leave you it leaves you with the fuel cell is cool yes it is tech it's efficient well yeah mostly the portable version perhaps not as much as people would like to know which is worse can be most likely use because let's face it if you have it as a baseload station was used for yourself doesn't make sense from a conversion efficiency point of view I know I know that Horace is talked about this on a Sim car in Michigan on Monday to talk about and have it out with them but for the moment at least let's leave it there that's hydrogen that's yourselves than anything else really say about that so I just take a moment out of our second sponsor this episode and that Lynda.com.com is an easy and affordable way to learn you can instantly stream thousands of courses created by experts in the fields of business software web development graphic design audio and lots and lots more weight to me list here they have an enormous library of tiles to choose from with new courses and every day to make sure the library is both relevant and up-to-date they work directly with experts from many different industries and software development company is to provide you with the timely training you need often on the exact same day the 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is built it's built some as you demolish a house and start again there is only as a limitation as to how much you can do and there's obviously also limitations based on the kind of house that is so if my house for example I live in is a slab on ground brick veneer are with a corrugated iron roof now that's can be very different to a lot of North American listeners and a lot of European listeners and they can have most likely tiled roofs they may live in our houses with a basement and attic they may live in houses that are single-storey split-level above ground you know it is very unlikely that that you were all in all different kinds of houses and some of things on the talk about will apply and some of them won't so if it doesn't apply to you just bear with me it applies to somebody and does apply to you well I guess you seem to think side is my focus predominantly on heating and cooling little bit about lighting but let's just lessons to heating and cooling because heating and cooling is a lot of the energy that we use on a day-to-day basis hitting the winter cooling in the summer if that was not obvious so the value of you is in the U is often quoted it's actually a measure of the amount of heat transferred through one square metre of material with a temperature difference of 1C cytometric new but that's products it is for this so your senior mentoring the user UW arm of a particular material essentially as the thermal transmissibility thermal conductivity measure that we can use so installation less about insulation in the ceiling now if you tiled roof it's a bit like a brick wall insulation right in the matter is very similar to that but it's corrugated iron like mine then it's absolutely vital that you have insulation ceiling if you tiled roof it's not quite so critical still useful to have arm because the that the thing is that the Yahoo material itself acts as a thermal arm thermal buffer of sorts it's our the thermal mass again it starts out cool in the morning sun comes up it gradually warms up and then the sun goes down it takes time and ours even to dissipate that heat back into the environment so you'll find it in the early hours of the day brick house with the arm with a tiled roof is actually quite cool even though if you step outside it's usually 510 warmer outside than is inside the house once you get to about nine or 10 in the morning you in summer that's all gone and it is now quite hot and then of an evening sun goes down it will be a few hours to 3 hours after sunset before that he dissipates again so it retains heat but also provides better buffer sance hysteresis is there a way of saying anyway so arm there is a great site are called super homes UK and it gives a good list of the different materials and their respective U values for installation summer pluck out the ones arm for example here some metal roof with no insulation has a UW of 0.9 or as a 1 inch at the same route but with a 1 inch thick which is 25 mm fibreglass insulation drops that back considerably to 0.26 to get down to 0.05 however you need to go to 6 inches which is 150 mm of fibreglass insulation that's really quite thick now if I now being a little bit okay I'm astray side pluck some Australian numbers but the average floor area of a house in Australia is 220 m song to use that roughly is my roof area it's close enough in a food government work or even non-government work is not government work with a 15 temperature difference between the inside of the house on the outside of the house with no insulation were looking at a 3 kW heat loss with 1 inch of fibreglass insulation were dropped down to under kilowatts only 850 W of loss with 6 inches of insulation is down 265 W of heat loss so that don't get in it that's huge absolutely enormous and a course that wrote that goes both ways so if you try to call the house that the overheat is coming anyone stop coming so that it gives you an idea of the impact that it has the problem I've got though I so that's fibreglass insulation right well fibreglass is just one kind there are so many different types and brands it is not funny here is a list of five finally named ones single sided poly we foil single sided pie we foil with after 1.5 glasswalled bats single sided poly we forward 30 mm equally reflective eps board bubble foam foil double sided antiglare foil and a course of action, to stop that there's a lot okay and is obviously difference insulation will have a different arm transmissibility so let's just you know what is wrong with those figures a safe basic fibreglass nothing fancy just to give you an idea anyway rights insulation the walls obviously to cons was internal and external walls so building the brick you know concrete and rock blocked enemy mice a roadblock I think so you so rock blocked for those that aren't short it means is that they will take a mould and I will cast in concrete usually it's in the shape of a large rectangle and it's got two holes and two large square holes in it and they will stack these are interlocked usually and with bricks and mortar and then I will fill them up at Rio reinforcing bar I was and is referred to as Rio bar in through the middle and pouring concrete Reebok river must also called rib we: cinderblock there yes interlocked they are fantastic and you feel that up with concrete and it makes a really super strong thick wall as opposed brick which Jade is and is not stabilised with concrete through the mill typically solid brick get so you think that those are going to be the best for thermal insulation but the answer same problem of the roof tiles with our talk that is before today at Axa thermal mass they are hysteresis to heating and cooling cycle so you still want to have insulation on that because you decouple that thermal cycling of those breaks all the tiles all the roofing from the interior temperature of the house so are it's always installing insulation between the brick and internal wall cavity same kinds of numbers are but the gains will be different of course because the sunlight is not on some ice on the roof all day long from when it comes up when it goes down pretty much with the walls it depends on if their northern and southern and eastern facing in the time of year and the height of the house so two-storey was a single story there's there's many many variables the roof is the easy one to do the maths on that's what I've done it unto you your mileage will vary a not not why MMB are it's why am W fee yes is it will vary their weight may vary and I another part of walls and windows and not ones by Microsoft these ones are it's important as badger anyway art which is all I do value and outcome of the good joke anyway so double glazed windows everyone gets were hang on as everyone gets in Australia is uncommon to have double glazed windows and residential houses especially in Queensland New South Wales Western Australia go to the southern states like Victoria or down Tasmania it's more common but even then central heating is not is not a given many houses down down south do not have central heating and double glazing is sort of thing that people will put into a house that has our central heating because it saves so much on heating costs so his wife let's do some some rough maths and average house 70 m which is 750 ft of glass area in the house now that may sound like a lot to think about you've got some houses will have almost floor-to-ceiling windows broken up into two or four pieces you have doors that have got glass inserts you have sliding glass doors that are in all glass you know there's there's actually got out a lot of glass in houses and why because what we don't want to look at the inside of a war will see the pretty well be presumed pretty our view outside you know if you're in it if you're in a location where you got lots of grass and trees and you the dog running around outside tearing your air-conditioning pipes to pieces or your bike seats or your whatever cow football soccer ball anyway arm dogs and how or if you're unlucky enough to live in a place where you know you've just got the view of an alleyway well maybe the alleyway is pretty two members got some nice pretty graffiti on the joint look at whatever the point is you a bunch of glass in your lookout that you don't just look at a concrete wall influencing episode of the goodies where they they cover the perfect building that was so concrete yet not like that so when I want that we want glass but the downside is glass is terrible absolute terrible as an insulator arm so if we look at standard unscented 3 mm which is our native an inch thick glass with an aluminium frame or a lumen frame if you prefer to use the brand name it has a UW rate of 6.9 now remember the roof with without insulation was 0.9 is a 6.9 that's terrible again with a 15 or stick with another 15 temp to difference and that's degrees Celsius which is a difference in Fahrenheit of 27F than that attempt to difference yellow 00 let's say it's overnight yet that you're losing is 7.2 kW of heat just through the windows now if you try to maintain a temperature inside that house you need to top that up with heating sac that is heat energy lost continuous loss really not good harder so arm the best kind of windows in terms of like reducing the loss do not have a metal frame they have either a UPVC or believe or not at all timber get double glazing same, glasses find 3 mm thick was a 17/8 of an inch but you want to have a nice decent air gap between the two layers 6 mm as good as a quarter-inch air gap glass with those sorts of frames that drops it to less than half of jobs down to 3.03 inner so you only lose about 3 kW through all the windows and that is a heck of a lot better and still terrible but is a heck of a lot better now you know a lot of places that's actually quite expensive so a lot of places will stick with the steel frame you died they've got that they were over 6 mm gap in the W less than that all sorts of reasons structural reasons cost reasons blah blah blah point is though that that's the best you can get and of course single guys the worst you can get icy disposal wishing get is no glass at all just an open hole more in which case I will the transmissibility is of open-air mnemonic gate that also was a joke that was even less funny anyway if you really so if you really really really don't want to lose the heat out of the windows I got a great idea once you block up with foam insulation just block up yet we not using them very overview won't be so great but think of it this way you're saving energy anyway yes and is a little bit funny I think about that exactly not so ridiculous at night time if there is no one in the room you don't care you get if you have a control system might you could you could move a are an insulator into place of an evening and lock the place down relieving and I would say power on heating popped into a thick thick direct that we close in the evening and probably helps a little bit and that their packaging so that it would stretch the impact the packaging is the source of all truth RR I will leave it at that while the other option I thought I was maybe one day super ultra extra vision houses will have perfect walls that perfectly insulated that a perfectly solid and instead of having a hole in the wall you have a video screen with a camera looking outside because you know that the way that energy consumption is is reducing no maybe that'll work out to be more energy-efficient to lose power and then you can see a site you getting their pesky selector and the Dean exact trip this unaligned gay so angle of the house now I know I said it's kinda hard to shift the house once it's built that I thought about it if you houses on stilts it's actually possible to lift it and to move it if you wanted to mind you know that's statistically not very common to have house on stilts anymore are even in Australia it's not very common to expensive are but the idea anyways if you are building our new are in a position to do this are you if your house on stilts and lots of money I guess your Cuba sunlight shining the size of the house with eves or with no less windows on them during the summer months and allow the sunlight into windows and more readily are during wintertime and I are I guess the other idea is a dangling houses to angle windows and door such that you get a natural breeze basin of the locale that you live in its natural breeze pans prevailing wind directions are which artist realises the name of the previous apps opening I only completed in context the and that'll allow air to flow naturally through the house at all nice and well good and lovely because you just a municipality can't retrofit that but I have to mention for the sake of completeness in his balancing one choice of flooring now originally dismissed this boats it turns out turns out it's arm only really a big concern or improvement rather if you have an elevated floor or a cavity beneath the floor like no maybe a basement or maybe with the amount of space you crawlspace is only or maybe we're talking about multistorey building and nowhere you were running heating or cooling one floor on the building and not the other hand is getting a temperature differential causative differential is the issue that were fighting against fjords if your vehicle fooling everything equally and is a dividing wall dividing floor doesn't matter if it is all being called equally the minute average difference that is mapped inside or not you are only trying insulated from past the house that you are not air-conditioning your air-conditioning the outside world therefore there is a pretended differential between inside and outside protocol inside outside is too hot to cold your try control the insight hence insulation stops that you if you've got one room and how to try keep that one room: the interior was finding inside the interior was your contract that energy that cool energy or hitting one room and not the others like you may not hit the garrison sky, call clients and you inside everything around the garage but you wouldn't bother hitting the garage so is all that different temperature differential now my house is a concrete slab on ground which is quick cheap and simple but is also prone to things like well termite intrusion which is in good are stress cracking in the slab you blah blah who cares the a civil engineering problem okay the differences between lino are timber veneer hardwood really not that great in terms of their thermal conductivity that that the ceramic tiles aren't really that good error exhibit worse than that it turns out that backed carpet is in rubber backed carpet is the best but no matter how you slice it you need to lay thermal insulation that allows some airflow so that it stops any wood wood rotting yards if you've got water on either side which you you proper going to our but you know it doesn't than the drafting from the outside because obviously that kills it that kills the amount the effect anyway the problem is generally not the biggest bang for the buck the walls the ceiling the windows much easier to retrofit so most people houses don't bother you high-density living for example may be the same in London with terraced housing is actually very common but for reasons beyond just the thermal side of things also for sound insulation because you because you're your unit might be on the third floor terrace and you might have young people living beneath you or the other way round and the people beneath you are double-headed people upstairs wandering around playing loud music or doing whatever they may or may not be doing that is not suitable for children the corkboard and mineral wool bats of the most common materials used for installation floor are the payback periods that i.e. I saw: once I looked at Islington the show notes are the 3 to 5 year payback period they say the inciting suspended floor arm but only about 8 to 10 years which is not as good for a solid floor now honestly at the aggressor it makes sense to me that the suspended floor would be better because accounts can be more effective because you got more of an airgap in times of but the other problem is I have this website is it it is a lot of conflicting information out there and they show their working I would love to have gone through and confirm that honestly I just decided not to do the mathematical and move on but it's the last thing I'd try anyway because it's just the most difficult okay that is when am I throwing here before we wrap up on things you can do to the house in terms of insulation and it's kind of a guess is robbing Peter to pay Paul little bit its skylights now in a mirror so skylight big glass window in the roof damn right sometimes these other versions of them called solar tubes same kind of thing generally have a bit smaller so the idea is that let's say you've got a part of the house that you ordinarily would have lights on because it is too dark during the middle of the day or during fringe hours of the day from a likely like early morning late evening Bob sorry late afternoon not quite evening so are usually in the middle part of the house I would I would think you have this problem so what you can do let more lighting is install a skylight and I'll save you on running lightbulbs in that period on the electricity that bites this to problems I have first one is that all you will get a huge's skylight and you can't shut it so what if it's too bright and of the day anyone shut it well a lot of your sky you can't reach them to shut or they just are designer shopping mechanism are energies to damn hot theatre is a big it brings a lot of heady and during the summer and it's a big leak in those right and that's exactly what I want to explore so skylights also admit heat and a losing just like a window so it's a trade-off and I love those I'll talk about and so does the electricity cost saving of adding more light in that room outweigh the additional heating or cooling costs so I've let's run some numbers 14 inch solar tube but I found the website has a UW of 0.43 the cross-sectional area of hundred 54 in which is .1 of a square metre they are not huge but still a reasonable size or solitude and that same temperature differential 15 only results in 0.7 of what because it's so small there But it produces 6500 lm facet maximum but what windows we say okay that's were not the middle of the day we can assume about half actually operating this now our test cases the fringe and fringe times of day when there is less sunlight which is when it's going to be most useful because otherwise there otherwise notes as it is on this great but you would have otherwise been lit using the light not during the daytime but only on the fringe hours so will harbour numbered about 3000 lm networks out to if we are to an incandescent light bulb about 250 W worth of electricity now no one uses incandescent senile because incandescent stock so would switch to an LED to say goodbye and it's only consuming 25 W from a good LED for that amount of light intensity which mind you as I did Bob goes back to quite bright are you present my life X bulb are it's 18 what's in that superbright at maximum now 25 W is even more anyway so all these numbers and is running now all that assumes there is no thermal loss in the tubing arm there is no the roof cavity is Sara has been well insulated from the solar tube itself such that you don't get any heat losses there but even if we do assume we lose so say 10 W of heat is the roof space we are still well ahead of that 25 W for lighting that room way ahead .7 what's hard to beat that so ultimately yes it does make sense which is one of the reasons why you should consider them but of course is another little downside is you can make sure they're well sealed on both sides to prevent them leaking because that's not fun you've voluntarily punched a hole in your otherwise not leaking roof well only I say not leaking roof I presume your roof is not already leaking when you install the year the sold tube skylight but anyway right CA hopefully that sense of that question for anyone had now a lot of this talk about heat loss and you know and sound insulation it can be rendered useless if you leave every single window and door open then the air flowing through the house will predominantly set the temperature says more about in the wintertime when things are: the readings all shut up in your head in the house out one summer time when it's so hot you're trying to keep ahead of the windows closed and electronically the air-conditioning in your anyway but ultimately if far better stopping the energy loss at the point of use rather than trying to add more heating or cooling capacity at the input so let's just say arm I have no insulation in my roof none of my walls I've got you know none anyway and I'm in my entire arm of the entire room is covered in skylights it's one big skylight the ACO's huge heat loss we are in call the downs go take a 10 kW Inyo inverter air-conditioner battle very efficient so when you I do is you want to add insulation and double glazing in no added suspended floor with you with insulation at the do all those things might go get either 5 kW or for a 3 kW cooling unit and that's where you saving your energy so far better off doing the installation because that will cost you less and that will save you money in the long-term and if I do prioritise them I stood in terms of cost and ease I would start with ceiling insulation first dubious bank but then double glazing and the windows or inside frames are both hopefully wall insulation I would suggest would be next and then floor installation will be last irrespective of how you slice it up and I have said that before say it again is that it depends on the house that you've got some houses will have some yellow life resemble my house we we have no insulation in our wall cavities but we do in the roof down and I was a conscious decision that we made but then we have one wall mount air-conditioner and a whole house we don't have central air-conditioning no central heating so you are in many respects it doesn't matter as much air anyway all right last little bit_sprinkle on and then wrap it up and that is a little bit about appliances so this is all about energy efficiency is all about thinking about being greener and things you can do to save energy while his thing as much alert real silly things and was morale off one by one here we go when you buy an appliance think about the following things if it's gonna be running continuously or for long periods of time or regularly enough to know that it's on its on regularly then pick an appliance whose power is a small as possible for the task you needed to do they get hung up on other features just get one that doesn't consume a lot of power and all the things got energy star ratings and EPA ratings on and these ratings are designed to help you understand and some even have the actual kilowatt hour R rating on written on the front of them if you TBD really need a ridiculously huge huge TV set you probably don't know you really needed business can cost you a lot of electricity to run a big TV every few inches of that TV that you get as big as more and more electricity it's gonna cost driver do you really need dear any ducted air-conditioning you if you've got 10 kW of cooling load show you can forget ever disconnecting from the power grid Inyo no sold me a young enormous solar array and battery packs of your golf degree at some point be even be energy neutral and good luck with that so dear Renee ducted air-conditioning or fans good enough speaking offence fans are far more efficient than air-conditioning anyway and they take advantage of evaporative cooling that our body uses are go through forced air can force their evaporative cooling works fine well works relatively well to get stupidly hot or as ridiculous in high humidity that's that's the problem you were hilariously omitted in exactly get a frost free freezer and I say that not because I hate defrosting them the ice buildup in the coils no when ice buildup in the coils it kills the efficiency it makes work harder because ice as it forms becomes an insulator which then means that the cooling action of the gas inside the freezer is actually reduced as always doing it's keeping the icecold rather than the contents of the freezing cold out so you go deice those things regularly otherwise you you will have a much reduced efficiency Anthea Frost inevitable Hannah have to worry about getting your freezer is not frost free songs you defrost it regularly which of course no one does lay there like old as the door shut night dices in the way right time to defrost by which time has been running efficiently for months all right when healing a lightbulb get the longest lasting LED light bulbs you can get and think about the lighting level you actually need for the whatever the minimum activities in that room you don't need an 80 W worth of incandescent light in your room you just don't if you're if you're working on a study different story and besides which even if you are going LED desk lamp and no lower power focused you can begin focusing on the keyboard the on on if you're writing a book whatever you far more efficient than getting a high-powered LED bulb in the ceiling to be realistic and how much you actually need only the fridge freezer door open for too long again that's an obvious one and you hear recognition ERM a time close the door and leave open is an obvious idea is obvious is not surely to most people examine I've walked into these houses over how open plan was a thing there for a while so he open plan not confined it's awesome or something I know what the I don't get the attraction of open open plan has been so are and I have an air conditioner on one wall this enormous area and you look at the air-conditioner and I'm doing the maths in my head as you do she walk into a building the first thing I think is only be to use their own as British thermal units anyway all right good lovely did have anyone to add to that list presents molest I think you covered everything I would've thought of so doing that again will use to an referral John work and now I guess so is one that one potential explanation I guess they saw a rabbit up and so if you want a more menacing response with an John Geagea and check out my writing if you like the catalytic and the reasons were and because someone if you'd like to send any feedback please use the feedback from the website that we also find the shyness this episode on the contrast if there are topics you would like me to come you can suggest and vote on them@exhaust.com/topics want to sign for a free account you can follow pragmatic show on Twitter show announcements and other related stuff like forecasting like our final thank you to our sponsors for this episode are firstly an Internet you're actually like build with easy-to-use apps like filesharing logs calendars task management and more matronly URL..com/pragmatic to get started free to use the 10 people might recover quite sign up and start playing today and also Lynda.com to sponsoring pragmatic if there's anything you'd like to learn about and you're looking for an easy way to learn than Lynda.com can help you instantly 3000 supported experts in their fields of business software web development graphic design and not visit elderly NBA.com/317 Evelyn the new what are you waiting for well thanks again for listening everyone and thank you very much�
Duration 1 hour, 32 minutes and 38 seconds Direct Download

Show Notes

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People

Vic Hudson

Vic Hudson

Vic is the host of the App Story Podcast and is the developer behind Money Pilot for iOS.

John Chidgey

John Chidgey

John is an Electrical, Instrumentation and Control Systems Engineer, programmer, podcaster and runs TechDistortion and the Engineered Network. John has produced and appeared on many podcasts as well as Pragmatic.