joth

Netherlands already have exactly this: https://www.powerpeers.nl/about (referenced in the UK smart meter report on making supplier switching simpler) Back to the OP, I had a similar question of "how much PV" but it was solved by the planning office: having a south facing front roof pitch facing into a conservation area they weren't happy about any PV, but I suggested a whole-roof of inline panels and they said OK. So now we're waiting on the DNO to approve 8kW of feed in. In principle this was a simple decision - sure 8kW costs more than 4, but 4 costs more than 2, and being able to self-generate is not going to become less valuable as the energy network moves more and more towards electric. The only snag is the bureaucracy. After 3 months we got the PP for the PV, but after another 3 months we're still waiting on the DNO to reply to the G99 request to connect 8kW to a single phase. For those that say "just phone the DNO for guideline on...." I'd love to know the trick as every time i spoke to them they said they could only reply if we made the application, and the application seems to have no limit on how long they can take to respond. And I bet when the do finally respond it will be a simple "no", with no indication of cost of installing 3-phase and it'll be another 4 months waiting for them to answer that question... :-/

I was surprised to discover this actually is a thing https://www.airconco.com/no-outside-box-air-conditioning/ This might not be totally terrible if they had a buffer tank and recirculate water through, and use that as a preheat for DHW and medium temperature uses like washing machine and dishwasher. Legionella compliance nightmare and highly disruptive to retrofit so I doubt this is their design in practice. But surprised they don't warn about increased water costs. It actually makes me sad as it's aimed at London flat owners, but SE is already running out of water and Thames water are one of the main culprits of emptying all the streams around us. If you have a stream going through your plot it might be a wholely different argument. But... You then probably have enough space to hide an external heat pump anyway. Edit to add: the above mentioned buffer tank would have to be incredibly well insulated and get used fairly frequently else this is just standing in the boat trying to blow your own sails, as Ed would say.

Same monoblock ASHP as heating and DHW, about 5kW. Mitsubishi is my M&E guy's go to make, but now we've agreed cooling is legal he's thinking Panasonic is better as it multiple flow temperatures and better cooling modes. I can see myself pouring over @ProDave's excellent research in the near future LOL, yes we're also doing external blinds and calcs say solar gain is going to be negligible. The only reason for the ott cooling plan is that I was getting advise from 2 sides to put heating in upstairs, and didn't want radiator clutter, upstairs ufh would have minimal cooling potential (had to be between joists due to limited head height so no slab, no thermal mass), but recirculating air via a fan coil had been discussed a lot here so thought we'd give it a go. The fact we were designing it this week also leaves its mark. If the air temperature doesn't go below 20 overnight, overheating is eventually inevitable however good the passive cooling design. Definitely, bit the limiting factor is probably not the capacity of the heat exchanger, but the maximum rate the MVHR system design will pass air over it.

Ouch! In practice the amount of cooling (or heating) you can get in through MVHR ducting is limited as MVHR moves air very slowly, and air has low specific heat capacity, so even worse value with that in mind. So after a lot of back and forth I've moved off that plan to using a separate recirculating fan coil for the upstairs bedrooms, as these can operate at a higher fan speed without messing up the MVHR balancing. As we have easy access to each room from the loft, I'm thinking a single ducted fan coil (maybe like Courier 42EM-09) branching to a small linear diffuser in each room. Return path via door-gaps to landing and a single larger return diffuser back into the loft plenum. I didn't know any of these words a day ago so hopefully that makes sense! My M&E guy thinks it's doable and looking into a concrete plan on this. It's quite a few parts, but may not be too bad compared to 4x fan assisted radiators and associated plumbing and control (or vs. 1x comfopost for that matter!). Also, very little bulk / space needed in each room for it (although the loft is going to become a ducting rats nest). If this was only for the occasional upstairs heating we're anticipating would be needed it would be way overkill... but the fact the design is being done this week has somehow made me very mindful of how useful having some highly effective cooling capacity would be.

We certainly did!! (Full disclosure: that was my team mate videoing; 4-tandem bike relay team, we'd just done the final pull to get to the top of the pass and they took over for the descent, as he has stronger nerves than me. Here's a shot of us rolling into Kansas early on day 4) 4 years ago now so details are hazy, but... they definitely do work, but I just didn't like wearing them. Large problem is unless you regularly train in >100F temps, and train actually using them, they just add another unknown risk which is the last thing you want on race day. (So long as it's <100F I found the body can self regulate enough given a reasonable forward motion creating movement of air. It's above 100F things rapidly come apart. And this is the only thing Fahrenheit is any use for) What helped me more is various "cooling towels": we kept a stack of them in cool boxes full of ice water in the chase van, each change you could drape those over and cool down quick. And the old favourite: nylon stockings stuffed with ice wrapped around the neck like a french man carrying onions. Exploiting the latent heat of vaporization effect, I now know to call it (thank you, MVHR enthalpy exchanger!)

I wonder if this works in reverse. It gives me a great idea for a highly efficient heater: if you could radiate heat energy directly at the place it's needed and minimise it going anywhere else, occupants would perceive it to be much warmer than the air temperature actually is, thus achieve comfort with the cost of having to bring the air up to temperature before it is needed. For rarely used rooms or poorly insulated/crafty houses the savings could be considerable, vs a traditional resistive heating element. Oh, looks like someone already thought of this https://spectrum.ieee.org/nanoclast/green-tech/conservation/graphene-heating-system-dramatically-reduces-home-energy-costs ?

API key= how they control who can use the weather service, and how much they can use it JSON= how you talk to the service Python= how Ed tells his computer what to do Sqlite= where Ed stores the weather data Cron job= how Ed tells his computer when the job should run The graphs look great! Building your own home weather station must be the modern maker's equivalent of a HAM enthusiast building their own radio transceiver, some really nice guides around e.g. https://github.com/initialstate/wunderground-sensehat/wiki And has to feel nicer than spend £460 / £6 a month on something like the loxone station / service ... Speaking of weather, the thunder just resumed here....

They do! There's even some with phase change material https://www.polarproducts.com/polarshop/pc/Cooling-Vests-c431.htm We tried several when we did Race across America. Hits 110F (43C) in the Mohave desert most days, makes any exercise quite exhausting (even if a 3000mile bike race isn't that already) In the event I found the vests too bulky so just kept with ice packs on the neck, but was good to have them on hand for emergency use

page 13 of that pdf makes it clear the heat pump is not ineligible just because it supports cooling: Air source heat pump [...] "They may also provide cooling." Page 11 also states the HP may provide water cooling Yeah the key thing is the energy used for cooling is not included in the claim for payment.

Wonderful news! I had two builders and my architects in our (pre-renovation) house today... very funny how the conversation came back to "what a good idea ASHP cooling is" Did he explain why he needed to know? I'm curious how much push back they do on this, given cooling is specifically permitted under RHI (but must not be included in subsidy calcs).

Couple thoughts - in a well insulated home you can do all the heating overnight from Economy 7 tariff, and the house will retain the temperature through the day. Even folks with lots of PV have to largely rely on this in the depths of winter, as that's when you need most heating and is when the sun is shining less. for cooling, you can redirect ASHP to cool via UFH downstairs and into a water-air coil exchanger for upstairs. This is exactly what we're planning. In terms of cost of running cooling, ASHP vs A/C unit shouldn't really be any different like for like. if you setup the A/C just to give a very short-sharp blast where it's needed and don't care it will heat back up fairly quickly it might seem cheaper than doing the whole-house with ASHP, but with water-air heat exchanger I reckon you could design the ASHP to have exactly the same profile as A/C if you wanted. (And for kicks: here's me just three months ago swearing I really was not going to get an ASHP. That sort of thinking doesn't last long after joining this place)

Yes, I'm becoming more comfortable with the noise risk -- previously I'd not have even entertained this location for it (higher up, and nearer our closest neighbour) I think the air transmitted noise with my idea could be quite manageable -- especially if we keep the unit well maintained (see other point about being harder to service up there). The real concern is ground transmitted noise/vibration coming through the flat roof, or wall if we bracketed it back there. This is the aspect that got the sharpest disapproval when I briefly floated the idea with the management. (and also: risk of it being rather unsightly, looming over the roof window)

Your son and I were in well tune this morning then! I was thinking about the Ed's comment (re. pity not to capture the ejected heat energy to warm DHW_ and realized in summer this is marginal gain as the building needs to be a "net exporter" of heat energy to outside regardless, to battle against overheating. So rather than focus on capturing the wasted heat export (which low grade energy anyway) and bring back into the hot water tank, wouldn't it be more efficient overall to focus on capturing the wasted cold-air export when running the ASHP to heat DHW. Cue son-of-Joe. My proposed solution [see quick sketch attached] that requires no new moving parts, is simply to relocate the ASHP from ground-level up onto the flat roof at the rear of the house. We have 2 rooflights planned there, if I make one of them open "backwards" with the aperture pointed towards the ASHP, then it's a simply a case of cranking that open when the ASHP is in heat mode and the indoors is overtemperature. A 1.5m x 1m long rooflight with 25 degree opening will give 1m x 0.7m opening, enough to capture a good portion of the draft, and being cold it'll naturally drop down into the opening anyway. Downsides are numerous: the noise and possible mess of having it on the flat roof there, right overhead the dining area, and outside a bedroom window. Probably also needs the flat roof re-specified to be safely walkable, for servicing. But on the flip side, it would make the pipe runs to the services room way shorter and simpler (no need to go under the slab). Realistically, unlikely I'll consider it further, but always fun to think about further optimizations!

@JSHarris great, thanks very much for that. I'm already going to have a water pipe loop from the ASHP to the loft anyway, as the plan is to heat upstairs via a split manifold arrangement, so I should probably just stop worrying and focus on that. When you've been lying awake sweating for 3 hours it's easy to think of ways to over provision everything!

@JSHarris Congrats on the install and hope you're enjoying a nice comfortable sleep! With the benefit of now having installed it and hindsight, what steps would you have made to future proof for this job when carrying out the original build? Are the A/c pipes the same for all manufacturers, so preinstalling it is a safe bet without knowing what unit will use it? Is the 10m limit for each of the pair, or total distance around the loop? My own thought would be an ducted internal unit in the loft and drop a duct down to each bedroom. So it's just a matter of pre-running pipes from service room up the riser to the loft. I *could* preemptively run them right out to the flat roof and seal them up somehow, but seems odd to add an extra penetration in the airtight layer until actually needing it.

This is useful to know. I think it's just a fan assisted radiator then? Several manufacturers of these about and I don't think they're particularly proprietary to the ASHP make, other than perhaps in the controller logic. We were recommended these for upstairs but I thought the fan a bit intelligent and gone for an air ducted solution instead. I hadn't thought about cooling mode with them, which could be very effective delivery into the room with the fan assistance. (And yes, I'm writing this laying in bed after failing to sleep for the last 3 hours due to the heat. And thunder)

See the eleven bullet points here: http://www.hse.gov.uk/construction/cdm/2015/principal-contractors.htm

In this case I'd do the insulation and other measures (airtightness + MVHR?) and leave ASHP and PV for future upgrade possibilities. PV + ASHP (and other technology solutions) are only going to improve efficiency with time and get cheaper, whereas insulation, airtightness and ventilation have to be done from the outset or are going to be way more expensive to fit later. Plus, the ASHP and ufh (and aircon) will work so much better if the house is built to not need so much heat input

No particular order. insulate, airtight, ventilate right. Assume and (prepare to) optimize for an all-green grid: batteries, car charger, ASHP, induction hob, solar PV, demand-side response etc etc. Minimize concrete use If (re)developing property in groups or blocks, consider district heating or shared ground-source loops and shared water recycling plan. Choose location to minimize commute/travel needs. Can be the hardest thing of all in plot-finding. Be Awesome. Contribute to, and benefit from a fantastic online resource that aids and educates others looking to do all of the above.

The other thing to to keep in mind is fire escape requirements. At this point I understand kitchens and bathrooms are exempt from needing opening windows, but for anyone reading in future I expect it's worth double checking this with your local friendly building control ...

If you don't have MVHR, another option is a recirculating down draft, and the a separate extractor fan over on the wall. For building regs only the latter is strictly needed, I think

@dpmiller nice price! At least, less rip-off-britain price. I'm sure the Heatrae Sadia mark up is justified by the WRAS certification Looks like this one is about 40% efficient vs up to 78% in the vertical mounted ones. I need to dig around and see how they compare for pressure drop too.

Just wondered, did you get to check it, and does it need any maintenance to date? Some of the guides (e.g. Q-Blue's own) make a big deal about requiring easy access to the device in case of maintenance or replacement(!) needs. But the UK reseller Showersave calls it "fit and forget" but still have a bit about easy access in the installer's checklist. Our ensuite is going to be immediately above the downstairs shower room, and it'd be ideal to put the exchanger into the void behind downstairs shower, except that'll be relatively well boxed in. (Well, same as the rest of the plumbing, shower controls. etc which probably have the same disclaimers). The other obvious option would be to put a linear heat exchanger under the downstairs shower and have upstairs shower cascade down into that too somehow. I just fear the complications of pipe lengths and overwhelming capacity of the exchanger (on either waste or the fresh water side) will make that a bad choice (given downstairs is more rarely used).

Wowzers! - £140 [2 sold] Did you see what happened to the Zypho? Now sold under license as Heatrae Sadia, £1450 RRP (yes, literally added a zero) but now on Special Offer Half Price (etc) (EDIT to add -- ah yes, I see you found them sold in UK for £800....)

Nice, that's what I was wondering/hoping too. I guess the challenge is can it reach it on the very coldest of days. With PCM, it's kind of all-or-nothing situation. Looks like Jiangsu Gomon do plenty of 2-stage high-temperature monoblocks, but it'd be something of a disappointment if that is it.