Heat Pump system needed for market garden
Can anyone recommend a cheap self install aircon heatpump system that will allow
- settable summer cooling down to 1C for garden produce storage
- settable winter daytime heating
The system would be in a largish garden shed with mains electricity supply.
If I were in your position @geo3geo I'd be going to AliExpress and Alibaba and putting those requirements to them.
Aircon and heat-pump devices of the sort you're looking for will cost less than £2000 direct from a Chinese supplier.
The internal mechanics are the same across most ASHP units.
The 'Western' manufacturers simply buy in the component parts from China and then add their own control board, software and App.
So you're not losing out much by sourcing the unit yourself.
As a DIYer you're not interested in installation warranties, nor are you limited to appliances approved by MCS.
The two issues you do need to be aware of are these:
- the Building Regulations noise emission requirements (42bBA), which are discussed elsewhere on this forum
- the handling of any refrigerant gases, which might need a licensed operator; see this post
Save energy... recycle electrons!
Hi @Geo3geo, I tried to reply the other day but the forum was playing up. Storage temperature of 1degC is way below that which comfort cooling split a/c heat pumps can attain. You need refrigeration not a/c - different refrigerants, evaporator coils, etc. There's several key fundamentals to consider; storage temperature, storage humidity (essential criterion for fresh or live produce), quantity of produce to store and throughput - how much produce at what temperature entering?, insulation value of cold store structure. I would respectfully suggest this is a specialist refrigeration enquiry to be put to a reputable and experienced company. You can try the DIY route for fun, but you'll need an F-Gas registered company in at some point to install and commission a system. Pre-charged internet purchased comfort cooling is a non-starter as it's not designed for refrigeration and cold store applications.
To give you some idea of equipment and cost (excluding install) consider cellar cooler refrigeration kit, which can provide space cooling to lower temperatures, but not humidity control. These systems are by J E Hall, the UK market leader, but the R410A refrigerant is being phased out, and is now expensive to buy.
I agree 90% with @allyfish is saying about refrigeration equipment and needing a registered gas operative.
However, I would still recommend looking at the Alibaba (& AliExpress) sites to gather ideas.
Here's the results from me searching for Air-cooled Refrigeration Equipment on Alibaba.
The range of possible solutions is interesting.
There are products here which run from a small unit to fit into the back of a DIY-built wine cooler right up to a full walk-in cold-store!
Not all the products use compressed gas.
Other technologies are available, and their operating cost will vary accordingly.
It depends on what volume you wish to keep cool and at what temperature.
If you narrow the search to 'manufacturers', you would expect to find some who have exhibited in a European show.
They may already have an agent in the UK.
A colleague of mine recently visited a couple of solar energy exhibitions (Germany & UK).
He came away with a substantial ex-demo suite of inverters & storage!
Save energy... recycle electrons!
You get what you pay for. You can do it on the cheap, and for a DIY project why not? It's a bit of fun and you can get some bargains. It it is for a business venture or professional interest I would advise caution. If equipment has F-Gas refrigerant and needs professionally gassing up I would find a local company willing to do this up before buying anything, and check the refrigerant type with them. There's some good prices on R410A equipment, but that's no coincidence - it's being phased out in the EU [including the UK] under F-gas legislation, and new R410A-based equipment will be prohibited from sale early in 2025. Wholesalers want rid = cheap kit, but costly to install and service. A future re-gas could be very expensive. A2L refrigerants such as R32 would be a safer bet at this point in time.
Check in particular the CE and UKCA compliance with stuff from China sold on the cheap. I've been in the refrigeration and HVAC industry 35 years and nothing surprises me. Fake certification is common, even Ex certified hazardous area equipment. It's true with ASHPs as well, with some false performance data to EN 14511. Several branded ASHP models sold in Europe and available for UK home delivery are dodgy. They're from one OEM in China strongly suspected of falsifying unit performance data. There's an EU investigation ongoing but the OEM will probably sell a million more units before that concludes.
Caveat emptor as they say 😉
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