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Heat Pump Convectors with ASHP!?


richo106

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Hi

 

I have been spec'd a 16kw Daikin Altherma 3 with outdoor and indoor unit (possibly combine hot water tank unit)

 

The guy also said Daikin do heat pump convectors instead of radiators and supposedly work better at lower temperatures than traditional (low temp) rads do.

 

They also claim to offer heating and cooling

 

Has anyone any experience with these?

 

My mrs won't be happy with the look (i'm sure) but the positives might out way the negatives

 

All help and advice/input greatly appreciated

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I assume they're talking about radiators with fans? If so then yes, we have them. We have Mitsubishi i-Life2 rads which were installed when we had the heat pump. They work, although I don't have anything to compare them with.

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1 hour ago, Iceverge said:

UFH an option? 

We are having UFH throughout the ground floor, then upstairs in both the bathrooms

 

Due to having 22mm T&G flooring and carpets upstairs we wasn't sure how effective UFH would be and the additional cost of insulating underneath so we thought UFH downstairs and then rads upstairs could be a good option. Then the guy recommended having HPC's instead of traditional radiators

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45 minutes ago, TW9 said:

I assume they're talking about radiators with fans? If so then yes, we have them. We have Mitsubishi i-Life2 rads which were installed when we had the heat pump. They work, although I don't have anything to compare them with.

Yes basically radiators with a fan, my concern is are they noisy?

 

Been having a look but can't see much on them regarding reviews etc

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Just now, richo106 said:
47 minutes ago, TW9 said:

I assume they're talking about radiators with fans? If so then yes, we have them. We have Mitsubishi i-Life2 rads which were installed when we had the heat pump. They work, although I don't have anything to compare them with.

Yes basically radiators with a fan, my concern is are they noisy?

Do they have a condensate drain? If not, the cooling function will be limited to 14ºC or so to avoid them dripping. (Also you need really good detailing on insulating all pipework, valves, pumps etc to run cooling at lower temps without creating puddles everywhere)

 

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1 hour ago, richo106 said:

I'm guessing what they mean by 'cooling' is being able to use the fan element of the convector to blow cooler air into the room


No - if this is a split unit then it will be a refrigerant link between inside and outside. My query is does that then run to the convectors as a refrigeration line or is there a heat exchanger internally that converts the refrigeration to heated/cooled water 

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18 hours ago, PeterW said:


No - if this is a split unit then it will be a refrigerant link between inside and outside. My query is does that then run to the convectors as a refrigeration line or is there a heat exchanger internally that converts the refrigeration to heated/cooled water 

They are simply radiators with a fan. Nothing more exciting than that. If you want them to cool you need to run cold water into them (yes, they have a condensate drain but ours aren't connected as we only use them to heat).

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Whilst that may have been the case previously, RHI as of 2018 is not affected by cooling capability - EssentialGuideforInstallers_V4__0_SpringSummer2017 (ofgem.gov.uk)

 

If the system is metered for payment however cooling consumption would need to be metered somehow and deducted to avoid short payment. Many products have built-in meters for this purpose though.

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1 hour ago, ReedRichards said:

Running an ASHP in cooling mode would prevent you claiming RHI or getting a waiver on Planning Permission.

This is an interesting point. Permitted development rights only cover one heat pump per property, and for heating not cooling purposes. There's a tiny bit of sense in that, as during the cooling season neighbours are more likely to have windows open overnight and hence be troubled by the noise. 

However I'd be interested if anyone ever successfully enforces removal of an ASHP in violation of this rule, i.e. that is used for heating and cooling without planning permission. I mean, they could hold it up with appeals, and ultimately all the owner has to do is turn off cooling mode, and they're back within permitted development space. I can flick it on and off from a mobile app, and it's virtually impossible for anyone outside the house to know it's being used for cooling vs just heating up the DHW tank anyway (DHW is in fact the noisier operation, although even that is still nearly silent for ours).

 

Wth 30M retrofit ASHPs being installed in the next decade (or whatever it is we're supposed to believe is the goal) I can't see this PD clause standing very long. It's simply unenforceable at that scale

 

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On 30/11/2021 at 15:38, richo106 said:

Yes basically radiators with a fan, my concern is are they noisy?

 

Been having a look but can't see much on them regarding reviews etc

They're noisier than a conventional radiator ?

 

Ours have two fans speeds. The fast speed is quite noisy. Not enough to stop you hearing the TV or having a conversation, even a quiet one, but very noticeable in a quiet room. It's been many years since I lived in a house with warm air heating but the noise level is similar to that.

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On 30/11/2021 at 11:58, richo106 said:

The guy also said Daikin do heat pump convectors instead of radiators and supposedly work better at lower temperatures than traditional (low temp) rads do.

 

 

Traditional radiators mostly work by convection rather than radiation.  They heat the air which rises out of the radiator and draws in more cold air from below.  You can increase the efficiency of heat transfer by blowing air through the radiator so a fan-assisted radiator can be smaller than a "traditional" radiator and achieve the same heat output (for any given water temperature).  If that's what "work better" means then it's true.  But if your guy is implying that the lookup-tables you use to calculate heat output from a radiator at lower temperatures are wrong and overestimate the heat output then that is news to me.   

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  • 2 weeks later...

I toyed last winter with installing a fan assisted hi level heater for our kitchen, as the kitchen was not warm enough and due to wall space available could not fit a bigger radiator. Just before winter i bought a Myson RC 10-6 high level fan convector, and now i am happy with it. As far as noise is concerned, it is acceptable in a kitchen but would not be in a living area. I have set the dip sws  so it only operates in the 2 lowest speeds and even in lowest it is noticeable.  It uses the second speed until it is within 1 deg of the target temperature then switches to the lowest. I am not sure if my thinking is correct, but i assume a high level heater will require a higher speed, as it is trying to drive the heat to floor level. I knew the heat output of the existing radiator was low as it was shown in the initial survey before the heat pump was installed. One other thing that may be of interest, i am only 3 days away from the first full year of using a heat pump and the total KW used today is 3948 kw. The house is 2 bedroom ex council built in 1937. with a total of 8 radiators, 2 towel rails. I hope you all have a good Christmas and please stay safe.

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