Heat Pump integrated into Hot Water Cylinders (Vaillant, Daikin etc.)

Screwdriva

https://www.youtube.com/watch?v=gBh510zhvAA

Finally, actual consumption figures on one of these!

Even at the highest stated consumption of 88 kWh this past October (assuming a tariff of .34p per kWh) , the Daikin heat pump cylinder appears to reduce hot water expense by 50% compared to the Viessmann 200-W, which used 560 kWh (£30 vs. £59) in the same month to heat a 250L indirect unvented Megaflo at the same storage temperature, also running a weekly anti- bacterial cycle. 

Regardless of your views on heat pumps to provide household heating, I can find zero argument against the technology for hot water assuming you have an area where the cylinder can be stored. Airing cupboards near bedrooms won't do sadly, as the pumps are a bit too loud. The financials are even more favorable when inefficient gas or oil boilers are compared. 

Only one other option in the UK though - the Vaillant AroStore. 

70sbudgie

Even if you didn't go for A2A HP for heating, wouldn't this compliment an ASHP for wet heating? It would enable the latter to be designed for a smaller capacity?

Screwdriva

70sbudgie said:

Even if you didn't go for A2A HP for heating, wouldn't this compliment an ASHP for wet heating? It would enable the latter to be designed for a smaller capacity?

It wouldn't work for us as the cylinder is right next to the bedrooms - the noise would lead to the wife ensuring I spend the nights in the garage. But your point is valid if you have the ability to insulate for sound etc. Significantly higher SCOP if air is diverted into the unit from the attic during the summer too! 

A genuinely interesting case study would be a showdown between a Mixergy heat pump tank vs. one of these to determine optimum real world savings! 

2nd_time_buyer

Regarding the noise, when I looked at the specs they were comparable to a gas boiler. If it was plumbed in with inlet and outlet venting to outside, then they could be positioned in a sealed well (noise) insulated cupboard. In which case it could bring the levels down to practically inaudible. 

matelodave

70sbudgie said:

Even if you didn't go for A2A HP for heating, wouldn't this compliment an ASHP for wet heating? It would enable the latter to be designed for a smaller capacity?

The size of a wet ASHP is related to the heating requirement of the house, not the hot water requirement. Heatpumps don't do heating and hot water simultaneously. Neither do they work like a combi boiler either where the the boiler is sized to produce continuous hot water direct through the boiler rather than heating a tank.

70sbudgie

matelodave said:

70sbudgie said:

Even if you didn't go for A2A HP for heating, wouldn't this compliment an ASHP for wet heating? It would enable the latter to be designed for a smaller capacity?

The size of a wet ASHP is related to the heating requirement of the house, not the hot water requirement. Heatpumps don't do heating and hot water simultaneously. Neither do they work like a combi boiler either where the the boiler is sized to produce continuous hot water direct through the boiler rather than heating a tank.

If you had A2A in upstairs rooms, would you not be able to then size the wet HP just for the downstairs?

How do HP deal with hot water? They require a tank don't they?

Screwdriva

70sbudgie said:

How do HP deal with hot water? They require a tank don't they?

Yes, they do. This is the single biggest drawback to the A-A ASHP - lack of hot water capability. The heat pump integrated cylinder (the subject of this thread) is one way of addressing this. The other is the upcoming UK market launch of a Daikin A-A multi split unit with one dedicated port for a hot water cylinder. 

That said, I'm not sure how one would run underfloor heating with any A-A pump?

70sbudgie

Would a solar (PV) divertor work with the HP integrated cylinder? Or would the HP need a more continuous supply than that provided by a diverter?

I keep wondering whether an ideal set up would be small low temp wet HP for UFH on a ground floor, integrated HP cylinder for DHW and multisplit A2A for first (and subsequent) floors. (Then combine with PV and EV charging for the full compliment of electric retrofit). There must be a flaw in this? (Is it purely cost?)

orbit500

70sbudgie said:

Would a solar (PV) divertor work with the HP integrated cylinder? Or would the HP need a more continuous supply than that provided by a diverter?

I keep wondering whether an ideal set up would be small low temp wet HP for UFH on a ground floor, integrated HP cylinder for DHW and multisplit A2A for first (and subsequent) floors. (Then combine with PV and EV charging for the full compliment of electric retrofit). There must be a flaw in this? (Is it purely cost?)

Yes, you can’t use a diverter with a heat pump as it requires continuous for voltage power supply.
That set up, sounds good. I’d like to see something on the market that uses waste, heat or cold simultaneously. When you’re running an air conditioner in the summer, the outdoor unit is pouring out heat. With an appropriate heat exchanger that could be used to heat water. Also, I have an 18 kW pool heat pump which trucks out cold air, this could be used for air-conditioning.
I’m currently on oil which ironically is the cheapest per kilowatt hour right now. I’m thinking of putting in a 5 kW wet heat pump
Which would do hot water and most heating in all, but the coldest weather.