Air Source Heat Pump - coastal location

Dazed909 · 10-06-2015 1:41pm #1

Hi,

Does anyone have any experience of using an air source heat pump in a coastal location, i.e. very close to the sea?

I'd like to know if salt corrosion, sand etc are problems for the compressor.

Thanks

BryanF · 10-06-2015 1:49pm

Can you give us an idea of where you are at in your design process

What reassurance have manufacturers given you?
What parts & service warranties periods have been touted?

Dazed909 · 10-06-2015 1:54pm

Sure.

New build - not yet started but design, planning etc are all done.

Sales rep doesn't think it will be a problem but I'd love to know if anyone has any direct experience. I haven't spoken to any manufacturers or been given any warranties.

Thanks

Borzoi · 10-06-2015 9:23pm

Dazed909 wrote: »

Sales rep doesn't think it will be a problem but I'd love to know if anyone has any direct experience. I haven't spoken to any manufacturers or been given any warranties.

Thanks

It's not a compressor issue, but is an issue for the aluminum fins on the copper heat exchanger - the salt air will destroy the aluminium. Some manufacturers coat the aluminium fins with a polyvinyl coating to protect them, that's what you need. Ask the rep

freddyuk · 10-06-2015 9:40pm

The rep should have told you that unless the unit was treated for salty environment then it would be destroyed in short order. The unit takes in vast amounts of air to work and if this is salt laden it will quickly corrode the thin metal parts internally. There are units already treated but you need to find the honest suppliers.

Calahonda52 · 14-06-2015 1:22pm

The sea air will destroy the unit if not treated and one problem you will have how do you know it is actually treated with the right material which will also impact on the efficiency as it is it not as good for thermal conductivity as Alu.
In addition the salt will lodge on the fins, decreasing efficiency even more.

If you are that close to the sea, how about closed looped vertical geothermal?
Whats the site geology like?

ps: you need to think " very hostile environment " for all kit

thermal conductivity

Aluminum 205 W/(m K)

Polyvinylchloride, PVC 0.19 W/(m K)

So 1078 time worse!!

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

Alphonsox · 24-06-2015 6:09pm

I have the same problem and the same concerns and have been doing some research.

Some ASHPs come ready coated for a marine environment. The ones on my list at the moment are LG Therma V, Dimplex A-Series, L&C.

As they are ready coated the quoted COP values include the coating - doesn't seem to effect things too much.

I am currently building on the coast near Portaferry and am looking for to buy an ASHP (supply only). With the £/Euro rate at the moment I won't be buying in the north.

Anyone got any suggestions

Calahonda52 · 24-06-2015 10:28pm

The quoted COPs, which are not quoted as SCOPs which all good kit is quoted seems a bit lower than I would expect.

As I don't know the heat demand you have, I just think COPs of the high 2.X seem a bit low, when I see not coated rigs like this
" 12 kW output heat pump at SCOP (Seasonal Coefficient of Performance) 3.7, Air temperature -8°C/Water temperature 55°C."

The higher RH in coastal regions is also a consideration in winter

Alphonsox · 24-06-2015 11:25pm

I agree the lack of SCOP information is disappointing but hardly a differentiator in this market. I actually thought the COP values were ambitiously high in some instances (LG Therma V 5KW A7/W35 Cop 4.4).

The house is near passive spec and has a very low heat demand (~1.5kw with a Tdiff of 20C). I am looking for a monoblock in the 3-5kW range.

Calahonda52 · 25-06-2015 10:51am

The 1.5 kw is interesting because if u look at the heat pump, it may have 3 elec items, fan for the air, compressor for the work and another item for circulating the heat..
For the item you select, you need to look at the kw total (say 1.25kw) and ask yourself the question: with such a low heat demand, could I use that 1.25 kw better than spending x,000 on the kit which has annual maintenance costs.
Have you done the full LCCA for the heat pump?

Alphonsox · 25-06-2015 12:07pm

The ASHP is as much about DHW as heating. You are correct total lifetime cost of ownership is an issue. It does make sense assuming I can
- purchase and self install a monoblock ASHP for less than £2k.
- That it lasts for > 10yrs.
- I can perform any required maintainence myself and the cost annual should be close to zero.

Trying to find suppliers is proving to be the biggest issue. The government grants scheme greatly distorts the market with lots of companies willing to install for £££ but very few interested in selling a unit.

Dazed909 · 02-07-2015 1:21pm

Plenty to think about - thanks for the replies

Air Source Heat Pump - coastal location

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