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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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  1.  
    You can imagine a very long 'black box' with one end touching the surface of the sun, and the other end enclosing your solar panel, with its cable sticking out of the side. Heat enters the black box from the sun at extreme temperature, and leaves the box from the back of the PV panels at ambient temperature.

    The maximum theoretical Carnot conversion of sun's heat into electricity is given by the temperature ratio of (sun minus ambient) to (sun), **irrespective of whatever types of technology or physics happen inside the box**.

    The good news is the ratio works out at nearly 100%. The bad news is our current technology is far short of the theoretical Carnot limit, although with plenty of room to improve.

    Now imagine moving the black box so the hot end touches the warm waste air coming from an aircon condenser. The maximum Carnot efficiency is now low, close to 1%.

    The good news is if the waste heat is free and plentiful, you might not care if you only recovered 1% of it as electricity or hydrogen. The better news is you could use all 100% of the warm air to heat a house, if you didn't involve electricity or hydrogen.
    • CommentAuthordereke
    • CommentTimeFeb 28th 2019
     
    @WillInAberdeen

    This company seems to be doing a lot of shared ground loop systems:

    https://www.kensaheatpumps.com/airey-close/

    It seems you can also get Non Domestic RHI payments as well.
    •  
      CommentAuthordjh
    • CommentTimeFeb 28th 2019
     
    Posted By: WillInAberdeenIf there was a supermarket with freezers, it could sell their extracted heat into the ground loop.

    Since the heat being extracted from inside the freeezer ultimately comes from the freezer's surroundings, exactly the same amount of heat needs to be supplied to maintain the temperature of the surroundings. So it's more efficient to put the extracted heat into the surroundings.
  2.  
    AIUI supermarkets generate more heat from lights and customers and chiller motors than they need. That's why they have all those chiller units out the back. The freezer is not 100% efficient (Carnot again!) so it dumps more heat than it absorbs from its surroundings.

    But thinking about it, it would be neat if the supermarket also dumped (sold!) its waste aircon heat into the district ground loop in the summer, heating the ground, ready for the residential users to use in the winter.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 28th 2019
     
    I used to be really into this kind of closing-the-loop thinking - now it just hurts my head!
    •  
      CommentAuthordjh
    • CommentTimeFeb 28th 2019
     
    Most office and retail buildings generate enough heat to need cooling in the summer at least. It's the density of people and machines that does it. So selling that heat, or pumping it into the ground so it can be extracted in winter is very sensible. I was just pointing out that freezer units are something of a special case in terms of the heat balance.
  3.  
    Treasury have confirmed that new homes will not be gas heated after 2025, as per CCC recommendations. Can't find much detail. Eg does this include hot water heaters where heat pumps struggle. Does it include LPG or oil heating.

    How will it be legislated, a building regs change? Does it apply in Scotland? A "Future Homes Standard" is promised as well as incentives for small businesses to save energy.

    https://www.gov.uk/government/publications/spring-statement-2019-written-ministerial-statement
    •  
      CommentAuthordjh
    • CommentTimeMar 13th 2019
     
    Sorry, but where did you find that information? It doesn't appear to be in the document you linked to.
    •  
      CommentAuthorfostertom
    • CommentTimeMar 13th 2019
     
  4.  
    DJH, its written at bottom of pg4 of the Spring Statement in impenetrable government-speak. The guardian have translated it into English since I posted, thanks for the link Tom.
    •  
      CommentAuthordjh
    • CommentTimeMar 14th 2019
     
    Well, no, the bottom of page 4 talks about the decarbonisation of gas supplies by increasing green gas. The bit above about the Future Homes Standard talks about low carbon heating, which gas might be considered if it is 'green' gas. There is no statement about banning gas in houses.

    The Guardian article similarly says 'Hammond appeared to row back on implementing the full recommendations from the government’s advisory committee on climate change last month, which called for new homes to have no gas for cooking or heating from 2025'. So they seem to agree with me.
  5.  
    Not following you there DJH. You mean this bit? Do you have any more details?

    "Gas boilers will be replaced by low-carbon heating systems in all new homes built after 2025 in an attempt to tackle the escalating climate crisis, Philip Hammond has said. In his spring statement, the chancellor said new properties would use alternative systems, such as heat pumps, to help the UK reduce its carbon emissions."
    • CommentAuthorArtiglio
    • CommentTimeMar 14th 2019
     
    Seeing as sustainability building codes were abandoned as a result of pressure from the house builders, who suggested that volumes of houses built would be reduced and cost per unit increased, is it really feasible that gas heating in its entirety can be phased out from 2025. Can’t see it.

    Developments with some sort of district heating schemes based around ground source heat pumps working from comunal open space rather than individual gardens, may work but then it leaves hoseholders reliant on and tied to service contracts etc.
    Borehole gshp in each garden would probably be preferrable and with sufficient demand perhaps costs would reduce considerably.
    But surely it would make sense first to have a housebuilding industry that can build tight well insulated homes requiring minimal gas to heat them would be a good first step, plus look at encouraging/subsidising improvements in pre 1970’s housing stock in terms of energy efficiency.
    Just a lot of hot air and guff to fill out a spring statement at the moment.
    •  
      CommentAuthordjh
    • CommentTimeMar 14th 2019
     
    Posted By: WillInAberdeenNot following you there DJH. You mean this bit? Do you have any more details?

    Do I have any more details of what? Which 'bit' do you mean? You are the one that claimed a particular document said something that it does not.

    "Gas boilers will be replaced by low-carbon heating systems in all new homes built after 2025 in an attempt to tackle the escalating climate crisis, Philip Hammond has said. In his spring statement, the chancellor said new properties would use alternative systems, such as heat pumps, to help the UK reduce its carbon emissions."

    That's a quote from the Grauniad article not the spring statement and is full of errors as is usual for the Grauniad. The statement - that you provided a link to - does not include the word BOILER nor the word PUMP, let alone the expressions 'gas boiler' nor 'heat pump'. The same goes for his speech, which is at

    https://www.gov.uk/government/speeches/spring-statement-2019-philip-hammonds-speech
    •  
      CommentAuthordjh
    • CommentTimeMar 14th 2019
     
    What Artiglio said +1 Plus the point I already made about electricity generation capacity.
  6.  
    Posted By: WillInAberdeenTreasury have confirmed that new homes will not be gas heated after 2025, as per CCC recommendations. Can't find much detail.


    Well DJH, you've lost me now. I have not 'claimed' anything, in capital letters or otherwise. If you don't like the guardian, then many of the other papers and broadcasters have also reported today on the Chancellor's announcement, or you could try the BBC's coverage of the Spring Statement. If you do know any more details about this policy announcement, then please do share them with us, I can't find much as I said.

    Artiglio, quite agree. The CCC's No1 recommendation was to enforce existing building standards.
    •  
      CommentAuthordjh
    • CommentTimeMar 14th 2019
     
    Posted By: WillInAberdeenPosted By: WillInAberdeenTreasury have confirmed that new homes will not be gas heated after 2025, as per CCC recommendations.

    Yes, that bit. Where is that confirmation stated?

    You posted that statement together with a link to the chancellor's statement, which makes no such statement. So where does make that statement?

    I don't think it's unreasonable to be asked to back up claims you make about what has been said.
  7.  
    I am not 'claiming' anything. I already pointed you to the relevant page in the statement. If you are doubting that the chancellor announced this, that's great, but you could try googling it before posting. That way you'd be contributing something to the discussion. It would be great if anyone who does know something about this subject could chip in.

    https://www.google.com/search?q=gas+2025+new+houses
    •  
      CommentAuthordjh
    • CommentTimeMar 14th 2019
     
    Posted By: WillInAberdeenI am not 'claiming' anything.

    Yes you are. You have claimed that "Treasury have confirmed that new homes will not be gas heated after 2025" and I have asked you repeatedly to explain where that statement was made, and you have repeatedly dodged the question. Either you have actually seen evidence that the chancellor/Treasury made that statement or you haven't. i.e. not third-party reports in doubtful newspapers. Which is it? Have you or have you not got evidence for your claim?
  8.  
    Strangest thing I've heard all week, and I've been watching Brexit. Do I have any "evidence that the chancellor confirmed that new homes will not be gas heated after 2025?" Apart from his Spring Statement, or the coverage in "doubtful newspapers" such as the Guardian, independent, times, FT, BBC, skynews, metro, or the responses from GMB, FoE, Greenpeace et al, or the government website?
      Screenshot_20190314-164744.png
    • CommentAuthorMike1
    • CommentTime7 days ago
     
    And in the written ministerial statement at https://www.gov.uk/government/publications/spring-statement-2019-written-ministerial-statement

    Clean Growth
    The government is determined that we will be the first generation to leave the environment in a better
    state than we found it. The UK leads the world in tackling climate change and delivering clean growth,
    preserving the planet for future generations. In the coming months the government will set out further
    detail on the following:
    ...
    Future Homes Standard – A Future Homes Standard, to be introduced by 2025, future-proofing new build homes with low carbon heating and world-leading levels of energy efficiency. The new standard will build on the Prime Minister’s Industrial Strategy Grand Challenge mission to at least halve the energy use of new buildings by 2030.
    • CommentAuthortony
    • CommentTime7 days ago
     
    Interesting the first time I have see talk about reducing energy use, this should be the main goal.

    As for world leading, we are not even close to the standards they achieve in Canada or Central/Northern Europe nor are we likely to be.

    Are we talking about delivered standards or design standards 😏
    • CommentAuthorArtiglio
    • CommentTime7 days ago
     
    They’re talking in a manner expelling massive quantities of male bovine excreta, the UK economy needs to be able to generate enough wealth to make such goals even vaguely likely. Really can’t see the construction industry and their suppliers being able to achieve this in 6 years even if all the detail was available today, but it makes for good sound bites and punts the need for any action well into the next parliament.
    With a bit of care developers could turn out properties with solid A ratings on an EPC, ensuring this happens might be a better target for 2025, in the meantime why doesn’t the govt. invest in genuine construction training/ apprenticeships which highlight the skills and attitudes required , plus investment into developing a broad knowledge and research base into affordable ground source heating technology.
    All alongside efforts to improve the efficiency of existing stock, most of us remember the days of £1 insulation from the diy sheds, always seemed far more sensible than posting low voltage lamps to people that just went to land fill.
    •  
      CommentAuthordjh
    • CommentTime7 days ago
     
    I still haven't seen anything from the official sources saying that gas heating will be banned. They talk about greening gas and they talk about banning fossil fuels. Nothing about banning gas. And specifically nothing in any of the original sources that matches what was originally stated here. The OP has consistently refused to state where exactly he got the words that he attributed to the Treasury. That's all I asked for and all I still want to know.
    • CommentAuthorArtiglio
    • CommentTime7 days ago
     
    Ok, yep i suppose if you inject 5% green gas into the supply and new houses only use 5% of gas used you’ve got round the language, but its not the headline that the statement was wanting to create. Just the usual weasle words politicians like to spout.
    Probably a target we’ve already met statistically.
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