Which ASHP are set up to cool

[ProDave]

1 minute ago, redtop said:

of course.  But then i am back to where i started.  With gas close by and no PV to reduce elec costs which option is cheaper / easier to install and run.

 

• ASHP + UFH downstairs and upstairs + water - air coil exchanger for cooling upstairs + hot water tank

V

• combi gas boiler + UFH downstairs + multi-room AC upstairs

Running costs will be about equal. except ASHP might be slightly cheaper if you don't have gas at all so no standing charge to pay for that.

 

Install costs won't be far off equal. Remember you will probably save £2K at least just by not having gas connected to the house, so the gas plus A/C install price would need to be £2K less than the ASHP plus water tank plus fan coil option, just to be equal.

[Jeremy Harris]

In a post in another thread I compared some running costs for a given heating requirement using different fuels:

 

 

[ragg987]

I suspect that the capital costs of your second option will be lower, both materials and services. Running costs are likely to be similar, but one advantage of Combi is no heat loss at the dhw tank.

 

If you are happy with the limitations of a Combi, that is probably the way forward today. But in 10 years? With the government intervening on new build I think it is only a matter off time before gas costs escalate faster than electric.

 

My view is that ASHP and PV are a great combination as surplus electricity can provide hot water, but the financial equation with no FiT is weaker.

 

[redtop]

agree, if i could have PV it would be a no brainer. Last house we had, a 5 bed 1970's detached we changed the old combi boiler for a new Veissman gas combi with integrated (small) hot water tank. That ran 2 showers at once no problem and cut our gas bill down a lot (the old system must have been very inneficient).

 

Now started looking at MVHR cooling using underground pipes lol, argghh (and yes i know they dont pump enough ait to make much dif but a slight cooling breeze would feel better).

 

What we have to avoid is the grand designs trap of fitting new tech because its cool; it has to work, be simple to operate and be easily maintained. Remember the grand designs waste water capture system that involved a bloody great heavy tank in the loft with a few thousand litres of warm standing water used to flush toilets.......

[redtop]

27 minutes ago, JSHarris said:

In a post in another thread I compared some running costs for a given heating requirement using different fuels:

 

 

so nexgen and no thermal mass is the way forward?  ?

[moldy]

On 28/05/2019 at 09:51, jack said:

 

I use a flow temp as high as 16°C and that seems to work fine.  

 

That article is BS. At the temps we run, I barely get a mist of condensation on the small amount of exposed metal pipework around the UFH manifold. It doesn't even generate enough to drip onto the floor. I doubt the floor temp falls much below around 20°C, so definitely no condensation there. I don't even bother with a thermostat - just turn cooling mode on when the weather gets hot enough for long enough, and program it to run when the sun's up so it's mostly powered by PV.

What type of heat pump do you have? Is it as simple as that for cooling -just design for UFH and put the ASHP in cooling mode?

[Jeremy Harris]

18 hours ago, moldy said:

What type of heat pump do you have? Is it as simple as that for cooling -just design for UFH and put the ASHP in cooling mode?

 

Most ASHPs can cool as well as heat.  They normally use the cooling function to defrost, so it's built-in.  The manufacturers may not openly advertise the fact that their units cool as well as heat, but several of us have found that it works surprisingly well.  I may have been one of the first to try this, with our re-badged Carrier ASHP (it has a Glowworm badge, but was also sold with a Kingspan badge, amongst others).  I found it to work very well, so adapted our control system to include cooling (just meant adding a cooling room thermostat, really.

[markharro]

Hi so to summarise what I have taken from this thread - using an ASHP on cooling mode can be effective to cool your slab on the GF at least. Upstairs you can connect the the ASHP somehow into your MVHR to provide some cooling to the air? Can someone confirm the exact bit of kit needed for the latter so I can ask my MVHR supplier about it? thanks

[ykhan16]

Funnily enough also looking at this what with the weather we're having!

 

We are going with ASHP with UFH downstairs and radiators upstairs. From what i've gathered through scanning the thread the simplest method would be running the ASHP in cooling mode with the UFH taking care of the downstairs- the neatest method for the 1st floor would be fan assisted radiators in the bedrooms. I cant however find these after searching- anyone can direct?

 

Second question- is it worth getting a more powerful ASHP than required? Would there be tangible benefits to the level of cooling?

[Dreadnaught]

I will be having ASHP cooling with my UFH for my bungalow. I think in reality it can only reduce the temperature by, say, 5º – 6º or so, so helpful but not a panacea.

 

Worth watching this. Unconventionally, they succeeded in cooling their ankles.

 

 

[Luke1]

1 hour ago, ykhan16 said:

Funnily enough also looking at this what with the weather we're having!

 

We are going with ASHP with UFH downstairs and radiators upstairs. From what i've gathered through scanning the thread the simplest method would be running the ASHP in cooling mode with the UFH taking care of the downstairs- the neatest method for the 1st floor would be fan assisted radiators in the bedrooms. I cant however find these after searching- anyone can direct?

 

Second question- is it worth getting a more powerful ASHP than required? Would there be tangible benefits to the level of cooling?

 

I'm currently running my ASHP (Nibe) in cooling mode with flow down to 11C. The pump runs for 10 mins dropping flow tempt to 11C and then creeps up to 15C until the unit comes back on again  after approx 20 mins.

 

So far today the UFH has been working exceptionally well. The downstairs is curently 23.3C and this has not moved since 11 o clock this morning. Current outdoor temperature 31.4C in the shade.

 

The radiators are also cool, however they don't help really help to keep the room cool.

I  did experiment by putting a tower fan on its side under the radiator however it causes a significant amount of condensate to accumulate and then drop off the radiator. So unless you can mix the upstairs water to keep it above dew point, or somehow collect the condensate then the fan assisted radiators would cause issues.

I was getting condensate when running the flow as high as 15C-18C, at which temperature the cooling effect for the UFH and radiators is minimal.

[Dan F]

@markharro

Yes, cooling the ground floor via UFH is very effective, especially if you have a passive slab as the reaction time is slow and a slab at 19-20C will keep at least the ground floor cool for quite a while.

 

The most effective approach to cooling the first floor using ASHP is via using fancoil units. There are a couple of thread in the forum already regarding this. 

 

You can use a MVHR post-heater, but these are much less effective and should only be considered if your cooling demand is very low (e.g passive standard + automated shading). They stop your MVHR from heating up the rooms, but won't really provide much active cooling.  We have one installed (first floor only) if you want any more detailed in-use information.

 

https://www.zehnder.co.uk/download/33114/121335/en_uk-100357.pdf

[jack]

46 minutes ago, Dreadnaught said:

I will be having ASHP cooling with my UFH for my bungalow. I think in reality it can only reduce the temperature by, say, 5º – 6º or so, so helpful but not a panacea.

 

I haven't watched the whole video, but how long did they allow the house to cool before deciding it didn't work that well?

 

I don't have temp sensing, but at a guess it's currently something like 20º C downstairs, with a 16º C outlet temp from the ASHP. Coming in from outside feels like walking into a deep, dark cave. It got to 37º C here earlier  today, and it's got to be over 30º C upstairs. 

 

Perhaps the cooling effect won't be so pronounced in a bungalow, given you have a warm ceiling immediately above the cooled floor. That said, even if you only get a 5º – 6º reduction, that could easily be the difference between a tolerable 22º C and an uncomfortable 28º C. I know which temperature I'd prefer to be sleeping in!

[joe90]

I do know our Jeremy reverse engineered his ASHP to cool his slab (and it worked) and I have the same Unit, however, 33’ today, 27’ forecast tomorrow and 23’ the day after. I won’t consider spending money on cooling till we have more hot days .

[markharro]

Anyone encountered this unit that Paul Heat recovery have just introduced me to = https://www.jablotronlt.com/en/futura/ Ive never heard of it before. Seems to have some sort of cooling function

 

 

[PeterW]

I’m looking at how to make the ASHP go into cooling mode as it should have just one -24v contact and I’ve been advised it will work fine but I’ve never tried it !!!

[Dan F]

40 minutes ago, PeterW said:

I’m looking at how to make the ASHP go into cooling mode as it should have just one -24v contact and I’ve been advised it will work fine but I’ve never tried it !!!

 

Our Vaillant has a dry contact for heating but nothing for cooling!  Forced to watch slab temperature and turn GF cooling on/off manually.  There not API or Modbus interface either. 😞   (using the contoller doesn't work given delay in change to room temperature).

[TonyT]

On the video he said it needed a £350 chip to enable the cooling on the valiant system at the heat geek hq.

[Dan F]

33 minutes ago, TonyT said:

On the video he said it needed a £350 chip to enable the cooling on the valiant system at the heat geek hq.

It's a £15 resistor from what I remember, not a chip!  I have cooling working perfectly, just imposible to control from outside Vaillant controls.

[joth]

11 hours ago, Dan F said:

The most effective approach to cooling the first floor using ASHP is via using fancoil units. There are a couple of thread in the forum already regarding this. 

I have it setup this way, UFH downstairs and a fan coil ducted into two bedrooms (so far) upstairs.

The house is holding a very nice 20-21°C.

The FCU is only 1.5kW not really enough load for a 8.5kW heatpump, wish I'd bought more of them, or a larger one , as they're harder to get now (Brexit and supply chain issues)

 

The ecodan is easy to flip from hearing to cooling mode, and then the two zone "call for heat" dry contacts become call for cooling instead. Using the cloud API or modbus interface you can set the flow temps too, I briefly looked at that level of control possibly to increase efficiency, but it works fine without it.

 

 

[TonyT]

7 hours ago, Dan F said:

It's a £15 resistor from what I remember, not a chip!  I have cooling working perfectly, just imposible to control from outside Vaillant controls.

Don’t shoot the messenger, that’s what they said ….. 

[gc100]

17 hours ago, Luke1 said:

 

I'm currently running my ASHP (Nibe) in cooling mode with flow down to 11C. The pump runs for 10 mins dropping flow tempt to 11C and then creeps up to 15C until the unit comes back on again  after approx 20 mins.

 

So far today the UFH has been working exceptionally well. The downstairs is curently 23.3C and this has not moved since 11 o clock this morning. Current outdoor temperature 31.4C in the shade.

 

The radiators are also cool, however they don't help really help to keep the room cool.

I  did experiment by putting a tower fan on its side under the radiator however it causes a significant amount of condensate to accumulate and then drop off the radiator. So unless you can mix the upstairs water to keep it above dew point, or somehow collect the condensate then the fan assisted radiators would cause issues.

I was getting condensate when running the flow as high as 15C-18C, at which temperature the cooling effect for the UFH and radiators is minimal.

Which Nibe unit do you have? I have a smo s40 unit but cannot see how to set to cool.

 

I would really appreciate if you can share how you did it?

 

 

[Luke1]

29 minutes ago, gc100 said:

Which Nibe unit do you have? I have a smo s40 unit but cannot see how to set to cool.

 

I would really appreciate if you can share how you did it?

 

 

I have the SMO 20 controller and F2040 8kW heat pump. 

 

I had to enable cooling in the Service menu (Holding the return button for 7 seconds brings up this menu) (At your own risk)

I have no idea if the SMO 40 controller is the same?

 

https://www.nibe.eu/assets/documents/23958/231765-5.pdf (See page 32, your system would be 2 pipe cooling)

I couldn't see anything on the SMO 40 controller about how to enable cooling mode. There was a simple check box on the SMO 20 controller.

 

[MikeSharp01]

16 hours ago, jack said:

I haven't watched the whole video, but how long did they allow the house to cool before deciding it didn't work that well?

2 hours -

 

I am in the middle of a heatwave wondering how best to cool the upstairs of the build so this is all very timely. Especially given you feel that your upstairs might be 30deg!

 

We have the passive slab, will have the ASHP, so now if I can find some small fan coil units, we have only vaulted ceilings with a small flat spot at the top which has limited room but I found this fan coil unit:

 

Image: https://www.hitachiaircon.com/hk/en/ranges/airside-systems/fan-coil-unit but I cannot find this on any Hitachi / Johnson controls UK site but scaling from the inlet/outlet pipes we might get it into the ceilings. Anybody recognise it?

[jack]

22 minutes ago, MikeSharp01 said:

2 hours -

 

Crazy. It takes hours for underfloor cooling to bring the temperature of the whole space down. 24+ hours would have been a better test period.

 

24 minutes ago, MikeSharp01 said:

I am in the middle of a heatwave wondering how best to cool the upstairs of the build so this is all very timely. Especially given you feel that your upstairs might be 30deg!

 

Well here's the funny thing: I hadn't been upstairs during the day, and guessed 30+ based on the temperature the night before and the fact we had an incredibly hot day yesterday. 

 

However, when I went upstairs last night, I was surprised to find it only warm, not ridiculously hot. If anything, it felt like the temperature hadn't moved at all from the night before, and I'd be surprised if it was 30 degrees. Best guess is probably 26 or 27.

 

The only things I can think that might have caused this are:

• it was overcast here a lot of yesterday, meaning solar gain was lower.
• I've had the underfloor cooling running 24 hours a day for the last three days, and that's having some impact on the temperature upstairs even though it's only directly cooling the slab downstairs. There'll be a small amount of cooling from the effect of cold air from downstairs mixing in the MVHR heat exchanger, but that alone surely can't explain the difference.