ASHP results

[Bugtownboy]

Interestingly, had our gas boiler serviced on Friday. Tried to have a chat with the (young) engineer about ASHP.

Quick intake of breath through clenched teeth - OK, maybe vested interest, but, based on the ability to retrofit to existing housing stock, he felt, and in a way, I tend to agree, we’re not quite there yet.

As a comparator, and we’ve approached ‘energy’ as another resource that we’ve tried to reduce usage. This year our predicted usage will be -

Electric - 1.3MWh, Gas (mainly DHW and cooking) 1.8 MWh, home managed hardwood logs 6m³ (approx 15MW based on 2.4MW per cube of hardwood) and approx 450 litres of petrol

[openspaceman]

Glyn Hudson has done an update video on their heat pump install as well.

That makes me more optimistic about ASHP for here, similar size house and construction and a lot warmer and drier part of the country.
I would love to rip up two ground floors and install UFH because the solid floors here that replaced the suspended were done badly back before we got here 40 years ago.Even doubling the radiator surface area in the two reception rooms is doable, we do not heat the upper floor currently as the wood stove convects heat up there but the existing radiators might suffice there.


One of the things about getting old is it becomes harder to justify capital spending because you never see the payback and this house will be gutted and extended once we are gone.

Does his reference to larger bore primary pipes just mean from heat pump to DHW tank and then distribution to radiators being 15mm or does the 22/28 carry on further before branching to house heating circuit?

[Swwils]

15mm will be fine.

For such a small property just get a multi split and install cassette as desired in each room. Forget wet system.

Ah yes the classic "imma be dead so nothing afterward matters" technique

[AGT]

Glyn Hudson has done an update video on their heat pump install as well.

That makes me more optimistic about ASHP for here, similar size house and construction and a lot warmer and drier part of the country.
I would love to rip up two ground floors and install UFH because the solid floors here that replaced the suspended were done badly back before we got here 40 years ago.Even doubling the radiator surface area in the two reception rooms is doable, we do not heat the upper floor currently as the wood stove convects heat up there but the existing radiators might suffice there.


One of the things about getting old is it becomes harder to justify capital spending because you never see the payback and this house will be gutted and extended once we are gone.

Does his reference to larger bore primary pipes just mean from heat pump to DHW tank and then distribution to radiators being 15mm or does the 22/28 carry on further before branching to house heating circuit?

You should watch his install video for clarification. It’s very good

[openspaceman]

Does his reference to larger bore primary pipes just mean from heat pump to DHW tank and then distribution to radiators being 15mm or does the 22/28 carry on further before branching to house heating circuit?

You should watch his install video for clarification. It’s very good

I did but must have missed that bit, it persuaded me I am not clever enough or competent to attempt this myself.

[openspaceman]

For such a small property just get a multi split and install cassette as desired in each room. Forget wet system.

Yes probably, a small ASHP and a couple of cassettes is probably the cheapest bet, especially if I increase my battery size. I like to have 100 litres of DHW and the wet ASHP would enable that where A2A wouldn't. All the time I can harvest and season wood it is a bit moot but outside of the summer months I depend on either gas or electricity for DHW. I shall be looking at off peak tariffs this autumn with a view to stopping gas usage.

Ah yes the classic "imma be dead so nothing afterward matters" technique

Not really, I am just being realistic, while I like and am comfortable in this house it is a bit quirky. My surviving offspring have houses of their own and would not be likely to move back here. The house is the only "unimproved" one in this street and the area has become highly desirable so will attract a buyer wishing to extend and gentrify it. Previous experience of refurbish and extensions means I am aware that not much of my renewables projects would survive to be re used.

[Swwils]

Get a monobloc for DHW then?

[openspaceman]

Get a monobloc for DHW then?

I may be labouring under a misapprehension but I thought the one in Glyn's youtube was a monobloc.

I thought the simple A2A units some have DIYed on here just used the refrigerant as the working fluid with the in house fan unit receiving the compressed refrigerant liquid that then returned to the outdoor unit where it was evaporated and vice versa when in cooling mode. I knew you could get splits that supplied two fan units but wasn't aware you could have a water heater.

The monobloc ASHP keep all the refrigerant cycle within the unit and circulate water (plus glycol in some cases) into the house so can do CH and DHW much like a gas boiler but at lower temperatures.

[Swwils]

You can get anything you like.

Monoblock into a coiled tank, or into a exchanger. Split unit into a tank, vrf between two sides of building etc.

It's basically legos with refrigerant in between.

I do hope we see some deeper penetration of co2 and propane units, these are so very simple and performant at these small domestic scales.

Btw glycol is normally not used in almost any monoblock, they generally rely.on the wet components always being heated - might be advised if you expect multi day sun zero power cuts or periods where the unit isn't on. You certainly wouldn't fill your whole heating system with it because you'd waste alot of energy running the pumps. The only time I have seen it used was glycol to monoblocks then a massive exchanger to the rest of the internal system so that side could run on water.

I'm a big fan of direct heating for HW, no need for returns or volume filling then.

[ALAN/ALAN D]

https://www.bbc.co.uk/news/science-environment-66359093

Sensibly written article.

It makes cense fitting in a properly designed / well insulated new build home. Grey area fitting in an old build with inadequate insulation / windows / radiators / pipe work.