Pool and House ASHP (should I get both?)

[sw25481]

I am about to make the switch from gas. My house is well suited, large but all underfloor heating and lots of insulation, however I also have a 45,000 litre outdoor pool I use only in the summer. Today I have a single 13kw gas boiler that I use for house/hot water and the pool via a heat exchanger. It is oversized. Without complicating the question I also have a fair amount of evacuated tube solar (which has a separate heat exchanger) and a heat store. It is all an integrated system of flows I have managed very successfully with a Resol MX controller for 10 years. I use as much gas in the summer, roughly, heating the pool as I use in the winter heating the house and hot water. In the spring and autumn I do not really use much gas as I have plenty of solar heated hot water and no need for heating the house or pool.

When I look at house ASHP they are expensive and seem to be optimized for low outdoor temperature and relatively slow flow with relatively high temperature increase. When I look at Pool ASHP they seem to be the opposite. Cheaper, high flow, low temperature increase optimized for higher outside temperature.

Can anyone tell me if I should really be getting both a house ASHP and a Pool ASHP? Practically it would be possible to do either, although slightly less complex plumbing if they are separate. I am worried the house ASHP will be poorly optimized for pool heating in the summer, especially having to go through a heat exchanger but does that justify the cost of a separate pool heat pump?

Thanks in advance for any help

[Mr Gus]

You really ought give a rough county location for an idea of temp & weather in general.
How big is the house? heating the core or E-V-E-R-Y-T-H-I-N-G ..& too what degree is comfortable versus tolerable versus cold (measured not guessed)
How many people, & othet nuggets will form suggestions for you.

Also, someone here is offloading thermal tubes if you wanted to look at bolting onto a pre-existing solar solution to chip away via expansion of your existing heating for improved pool heating potential.

[nowty]

I think the OP has answered his own question.

The two types of heatpump are optimised differently in terms of temp and flow. The OP also has evidently a large energy need. You could do some complicated maths but I think in this case its a no brainer to have two separate ASHPs.

Increasing the solar PV and thermal generating capacity is also something I would look at. If you use a heatpump then the footprint for solar PV is similar to a solar thermal footprint in the space you need for them.

[ClockmanFRA]

I have a ASHP on our Salt pool. About 4 years now.

But you still need a fair bit of electric to run it to get a decent 2c above the pool temp pumping back in to the pool.

We have a so called 7Kw ASHP but still needs about 2.5KW to run it.

However the figures from the manufacturer are not accrute.

We actually put in 2KW of electric we actually get out of the ASHP about 5.5KW.

Under EU installation laws, i, as a competent individual can no longer install a ASHP, even though it comes fully LPG charged. And i need a registered installer to connect up the two pool 60mm dia pipes and the electric cable, and that would cost me 1200e, the bastar.s.

I was going to install another 2 ASHP ducted air flow heaters for the last house that i am finishing here, yea passive house standards, but again the admin and certificates required just price this form of heating out of the market.

Plus, talking to other folk around the World it seems that life span is about 10 years on a standard ASHP.

It is far cheaper and far more cost effective to put up another static PV array of 10 KW, and have it AC coupled to simple good quality electric underfloor heating, like we have in our other 7 buildings here. Some of our underfloor heating AC coupled to PV, has been running a good 16 years.

After 10 years or so or when the pool ASHP packs in, i will install a 7Kw direct heater for the Pool that also runs of the PV system we have here.

So for us, any future ASHP's are dead projects for us at the present time.

[AE-NMidlands]

Given that solar thermal is 80% efficient, with minimal electricity consumption, I wouldn't rule it (solar thermal) out. (Unless you insist on swimming in hot water outdoors in winter!) When you will be buying kW.hr anyway, as we don't get sun when we most need heating.
A

[Andy]

Would running pool water straight through a solar thermal setup cause corrosion issues? Or is a heat exchanger always required? I guess that could be a very simple setup and just drain it down when the frost season starts. At the end of the day the area required is very similar. PV through ASHP gets the COP gain making the two technologies very similar in output for solar input.

The benefit of PV is that you then have that available for the seasons you are not heating the pool.

[Mr Gus]

Pool specific heat exchanger Andy (many conversations on it from st elsewhere) due to the aggressive nature of pool chemicals.

[Andy]

Pool specific heat exchanger Andy (many conversations on it from st elsewhere) due to the aggressive nature of pool chemicals.

Aha thanks.

[Mr Gus]

Here's a bit more on the subject, arguing for titanium in some instances..

https://www.econology.info/forums/garde ... 16401.html

[Andy]

My poor little pump that's been pumping water round my kids paddling pool through a spa heater is probably not long for it then