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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.

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    • CommentAuthortony
    • CommentTime2 days ago
     
    +1 and +1 , my problem with DH is that there is big funding available, government and councils are clutching at straws.

    Culturally it doesn’t work in the UK , when repairs need to be paid for one or two can’t or won’t and it dies a death as above. Yes it works in US cities and some places in Europe but the track record here is almost non existent.

    Then, speaking as one living without a formal heating system, why do even need that stuff, murderously expensive and very disruptive as retrofit and should not be needed for new build, use insulation instead🙂

    And no new housing is not fit for purpose at least not as housing. As a means of making a profit it costs us more than they make - silly.
  1.  
    >>>Culturally it doesn’t work in the UK

    Rubbish, sorry - district heating is working just fine round here. 1000s of homes connected to the council's network, and schools, swimming pools, offices etc. They even pump heat out of the ice rink and integrate it with heating homes.

    https://www.aberdeenheatandpower.co.uk/

    Edit: that does remind me though: when I first joined GBF, the prevailing wisdom on here was that 'ASHPs don't work in the UK'. Does anyone here still believe that? The CCC worry that the great British public don't believe in ASHPs and that's the barrier to getting them installed in 20million homes.

    The CCC also don't believe the British building industry are going to replace or passiv-ise the housing stock in time for Net Zero, but they are hoping for a lot of retrofits.
    • CommentAuthorEd Davies
    • CommentTime2 days ago
     
    The things I like about the idea, in principle, of district heating are that they:

    a) can be much more flexible on heat sources than individual homes can, e.g., using a mixture of solar, wood chips and cheap-rate electricity via heat pumps from different places where the complexity gets amortized over lots of buildings and

    b) can store energy as heat more efficiently and for longer (the bigger the store the better the surface to volume ratio works) so somewhat-interseasonal storage becomes practical.
  2.  
    Posted By: Ed DaviesThe things I like about the idea, in principle, of district heating are that they:


    The thing I don't like about the idea, in principle, of district heating is that they can have high transmission losses. I have seen where the route taken by the district heating line was easy to see - because that is where the snow melted.
  3.  
    AIUI the Aberdeen council heating network is using some CHP, and they want the demand for heat to be spread out across the day to maximize the running time for their electricity generators. They are connecting up the leisure centres and schools, because they demand heat at different times of day to the home users. They are thinking about connecting up the sewage works and incinerator to recover waste heat and biogas.

    Most of their home consumers are in council-owned blocks of flats and old folks homes, which might make it easier for them to connect up lots of consumers in one go.

    We get some snow in Aberdeen and there's no sign of snow melt from heat losses, the new pipes are heavily insulated and deeply buried. But I have seen 1980s industrial steam systems which were badly insulated, like the old uninsulated houses of that era, maybe that's what you saw PiH?

    The next generation of district heating systems apparently run at 20-30degC so losses are negligible. Each consumer has a little heat pump to boost the temperature to whatever they need to run their CH/UFH. Commercial users such as supermarket chillers or office aircon will find it easier to dump waste heat into the network and get paid for it. The network operator tops up the heat with ashp/gshp/wshp/whatever.
    •  
      CommentAuthordjh
    • CommentTime2 days ago
     
    Posted By: Peter_in_HungaryThe thing I don't like about the idea, in principle, of district heating is that they can have high transmission losses.

    That's not really an objection in principle; it's a possible implemetation risk. Hopefully one that is becoming less common nowadays. It's like objecting in principle to electricity because people can be electrocuted, or to combustion fuels because they can be burned, or to fresh water supplies because people can be drowned.

    I like the idea of district heating that uses waste heat of whatever type. It is sometimes difficult to balance the demand for the heat with whatever generates it though, which leads to a reduction in overall efficiency and so an increase in costs and carbon.

    There was a piece on the TV recently about a very large new greenhouse that is to be heated by the heat produced by a sewage farm. That struck me as a good idea. There's some details at e.g. https://www.dailymail.co.uk/sciencetech/article-8217227/Giant-greenhouses-use-sewage-farm-heat-produce-vegetables.html
  4.  
    The district heating that I have experience was not low temp. utilising waste heat but a central boiler house (gas fired) distributing to flats with conventional radiator heating. The losses in such a system would be greater than a low temp. system with a local heat pump to boost the temp.
    I would support a system using waste heat (aka by-product heat) especially if transmission is at low(ish) temps but I am not sure about centrally produced heat just for the purpose of heating remote buildings.
    • CommentAuthorEd Davies
    • CommentTime2 days ago
     
    Posted By: WillInAberdeenEach consumer has a little heat pump to boost the temperature to whatever they need to run their CH/UFH.
    And DHW?
  5.  
    Guess it could if you wanted, a single stage heat pump could get from say 20 up to 60 degC with a good CoP.

    Did you ever look at those DHW cylinders with an integrated air-water heat pump? They must operate over about that temperature range.

    Or you could heat your cold feed to 30degC using the DH in an exchanger, then top it up to shower temperature with an electric element.

    The CCC's consultant envisaged 20% of homes using DH by 2050, I guess mainly city flats, I suppose that could work.

    I'm more doubtful about the 20% envisaged to be using hydrogen or biogas for DHW by then.
    • CommentAuthorMike1
    • CommentTime21 hours ago edited
     
    In the UK, District heating is also in use on the former London Olympic Park - https://www.engie.co.uk/about-us/references/ele-district-energy/

    Top user though has to be Iceland, where it serves around 90% of the population, mostly using geothermal heat.

    Lots more info at https://www.euroheat.org/

    Particularly in cities, where gas boilers are a significant source of NOx pollution, and where there is a limited ability to install heat pumps in densely packed areas, district heating will surely have a major role to play.
    • CommentAuthorArtiglio
    • CommentTime7 hours ago
     
    But Iceland has the major advantage of all the heat being easily accessible and at far higher temperatures along with in serving 90% of the population the the management costs are much less per household.
    The stratford example relies on biomass ( is it in receipt of subsidies?) is only for 40 years , will the pipework in the streets be good beyond that?
    Its difficult to see any retrofit district heating system being economically viable the installation costs will be huge, the replacement of existing boilers with HUI’s is likely to be at least that of changing a boiler alone, who bears the the capital investment cost? Will it be as an extra to the standing charge a lump sum or combination.
    The beauty of the domestic gas boiler is that they are generally very reliable and cheap, the householder manages the maintenance and repair relying on the existing skill pool who again are relatively inexpensive over the boilers lifetime.
    A district system will have a management structure offices, hse departments , specialist engineers etc etc all of which bump up cost considerably. The costs are going to be substantial, its hard to see an argument for it compared to spending similar sums on insulation and a much reduced heat requirement that could be satisfied with electricity.
    •  
      CommentAuthorfostertom
    • CommentTime5 hours ago
     
    Posted By: ArtiglioIceland has the major advantage of all the heat being easily accessible and at far higher temperatures
    As well as so plentiful that no one cares about inefficiencies and losses.
  6.  
    Hi Artiglio, the Aberdeen scheme is generally regarded as having saved the tenants a lot of money and there's quite a high demand from other people wanting to sign up. The capital costs are paid upfront by the commercial operation company who install 'in bulk,' and then reclaimed through the operating charges which are subsidised by the waste heat coming from the CHP. Same commercial model as fibre broadband.

    The CCC's report generally agreed with you, they categorised all the homes in the country according to size location construction etc, and worked out the cheapest way to heat each category. For more than 80% that would be insulation+ASHP. For the remaining 20%, there were some city tower blocks of flats where individual ASHPs per flat were tricky to fit, so they proposed insulation plus shared HPs per block (describing this as District Heating if there are >6 users and Communal Heat for <6).

    They compared that against the rewiring/distribution costs required for electric heating in each flat, and the expected cost of peak-time electricity, and cost/space of DHW immersion cylinder to replace gas combi. They did recommend electric heating for some categories including heritage buildings where insulation+ASHP might not be acceptable.

    Worth a look, I posted the link somewhere above.
    • CommentAuthorMike1
    • CommentTime1 hour ago edited
     
    Posted By: fostertom
    Posted By: ArtiglioIceland has the major advantage of all the heat being easily accessible and at far higher temperatures
    As well as so plentiful that no one cares about inefficiencies and losses.

    You might think so, but it's not that straightforward.

    The heat is being depleted in some areas to the extent that they need to drill a new borehole each year to maintain the temperature https://www.icelandreview.com/news/power-plants-running-out-steam/

    They're also investing large sums in drilling very deep (4-5Km) wells through very high temperatures (400-500°C) and pressures (200 atmospheres) to access new resources for CHP plants, so not necessarily all that accessible either https://www.bbc.com/future/article/20161221-the-most-extreme-geothermal-plant-in-the-world

    And they didn't choose geothermal because it was cheap - it was part of their policy to achieve energy independence as a result of the 1970's oil crisis. Back then they were largely dependent on coal & oil imports, and they only had a few small geothermal plants. They also had to invest in developing the technology, despite then being one of the poorest countries in Europe.

    As for the cost, in 2016, it cost an average of €572 (excluding tax) to heat a 100m² apartment in Reykjavik, using 495 tons of hot water per household, so not particularly cheap https://www.thinkgeoenergy.com/geothermal-energy-giving-iceland-lowest-heating-costs-in-the-nordics/ The Average UK household gas bill in 2016 was around £650.

    BTW, it's estimated that the UK has big geothermal heat resources too, albeit at lower temperatures than Iceland, but little has been done to harness it's potential https://www.dur.ac.uk/news/newsitem/?itemno=21000
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