Navitron Renewable Energy and Sustainability Forum

HEAT PUMPS & Geothermal Energy => Heat Pumps => Topic started by: Home Farm on August 26, 2019, 08:10:35 AM



Title: What features do you look for in an ASHP?
Post by: Home Farm on August 26, 2019, 08:10:35 AM
For those of you that have purchased or are thinking about buying an air source heat pump, what are the main features that you are looking for?


Title: Re: What features do you look for in an ASHP?
Post by: todthedog on August 26, 2019, 10:03:02 AM
The right power output for the area to be heated/cooled. Don't  skimp.
A decent COP
Reliability, cannot be guaranteed  of course, a decent manufacturer rather than internet cheapo, we have used Mitsubishi in 3 houses over 20 years, France, Sweden and Wales and have been very satisfied.


Title: Re: What features do you look for in an ASHP?
Post by: Home Farm on August 26, 2019, 11:40:21 AM
The right power output for the area to be heated/cooled. Don't  skimp.
A decent COP

What would you consider a good COP?


Title: Re: What features do you look for in an ASHP?
Post by: DonL on August 26, 2019, 03:56:53 PM
Simple question with a complicated answer. The COP of an ASHP shoud be based on specified conditions in terms of air temperature and water temperature. So you need to ensure that they are quoting the COP based on the same conditions and can then compare between brands. The COP when heating to low temperatures such as those needed for a well designed room heating system at say 30 or 40C will be quite different to heating domestic hot water to 60C. Some ASHP's claim to have better performance than others under these circumstances but they can't beat the basic laws of thermodynamics.

System design is really, really, important and the ASHP must be well designed to meet all conditions including when it is -15C outside, but many of them do this by using an electric resistance element (COP = 1) to back up the heat pump in extreme conditions. Your design should show at what point this back up becomes necessary - the lower the better. It's better if the ASHP modulates to meet load rather than operating on/off, and if it is on/off you need a big buffer tank so it doesn't do it too often.

Maintenance is actually dead sample until something goes wrong! The annual maintenance for mine involves cleaning the waterside filter and topping up if necessary, brushing the fins clean, lifting the pressure relief valve and checking the RCDs., which I do myself.

I installed my Panasonic in 2015 and haven't had any problems yet. I have no basis for comparison with other brands so can't suggest which are better. Going with a reputable brand seems sensible to me too.

Once again, system design is really important. Many users are left unsatisfied because the design is inadequate or their expectations/method of operation are unrealistic.

Any heat pump operates best when maintaining a fairly constant temperature and running continuously. It is not necessarily ideal if you are out of the house a lot and want to bring the temperature up quickly when you get home.


Title: Re: What features do you look for in an ASHP?
Post by: benseb on August 26, 2019, 05:00:00 PM
A lot of the claimed SCOPs can be a bit misleading

We looked up the model numbers on the MCS website to get a more standard figure at a given water temperature.

Also we went for a big brand as Id had a more niche brand before (Husky 🤨😖😩) and it was a nightmare getting an engineer or parts

Were waiting for a 14kW Mitsubishi Ecodan to be installed in a couple of weeks

Ben


Title: Re: What features do you look for in an ASHP?
Post by: todthedog on August 26, 2019, 05:01:26 PM
OURS IS 3.5 kW Mitsubishi  heavy industries. Ashp air/air
We thought it worth paying a little extra for the latest gas

SEER - SCOP (Cool - Heat)   7.8 - 4.26
EER - COP (Cool - Heat)   3.47 - 4.0
Energy Label (Cool - Heat)A++ A++


Title: Re: What features do you look for in an ASHP?
Post by: Home Farm on September 02, 2019, 09:40:19 AM
Our air source heat pump has been in operation for five months, over spring and summer, so it is a good time to review the performance and efficiency of our Caernarfon 18kW Eco Air Source Heat Pump (ASHP) from Global Energy Systems.

Most ASHP owners in the UK use Mitsubishi, Hitachi or Daiken ASHPs, so it should be interesting to see how a British manufactured ASHP, made for the British climate, will perform and compare.

As part of this video, Ive addressed our coefficient of performance (COP), performance and efficiency, the control panel and settings for the ASHP, noise rating and some general thoughts.

As I am not an ASHP expert and still trying to learn, I look forward to receiving your feedback and comment.

I will do a follow up video in autumn and winter to provide a full performance and efficiency comparison.

YouTube: youtube.com/watch?v=P8cBKBTTLBw (http://youtube.com/watch?v=P8cBKBTTLBw)

Additional information and data sheets: http://myhomefarm.co.uk/air-source-heat-pump-efficiency-and-performance-review (http://myhomefarm.co.uk/air-source-heat-pump-efficiency-and-performance-review)


Title: Re: What features do you look for in an ASHP?
Post by: ecogeorge on October 11, 2019, 10:39:54 PM
Do Navitron still sell them ???
Got a bargin one from them at a clearence a yr ago -will be installed this winter -honest....... surrender:
George


Title: Re: What features do you look for in an ASHP?
Post by: todthedog on October 12, 2019, 06:19:34 AM
They do


https://www.navitron.org.uk/aquarea-t-cap-9kw-monobloc-heating-and-cooling