Air Source Heat Pumps

clockworks_2

Richard

Thanks for the pics, Never seen the wall mount units before. What do you use for hot water? Heat pump or immersion?

richardc1983

Andy_WSM wrote: »

Before I drew off a tank of hot water this morning it was managing OK, once I gave it a tank of freezing cold* water to heat it struggled to get back up to set point - in fact, in 5 hours it hasn't got where it was this morning - only 1C cooler, but not there yet.

I'm happy to let it have a break for a couple of days rather than kick the !!! out of it!

As said, temps like this are the exception here - I doubt it will happen again in the life of this system actually! No point thrashing it for the sake of not spending £10/£20 on electric / gas.

*I have a rain water harvesting system & the water is stored in large insulated tanks outdoors - you can imagine this water is VERY cold right now!

Problem is though as your room temps drop you have lost the "fight" with this cold weather to last another 10days at least you will have problems trying to recover the temps... so if it was me I would be using the system for heating and your electric immersion for the hot water if this is the same tank as it wont have to work so hard to do the hot water then as the tank will be warm.

Perhaps give it a helping boost iwth the gas fire running.

richardc1983

samtheman1k wrote: »

Is that not mounted too close to the wall? I would of thought that that would of restricted the airflow into the back, thus reducing the efficiency. I don't know about the LG ones, but the Mit ones require a minimum of 30cm.

I think its a bit of an illusion the space is about 25C and its open all the way round. I think the bunched up pipework adds depth you see.

richardc1983

clockworks wrote: »

Richard

Thanks for the pics, Never seen the wall mount units before. What do you use for hot water? Heat pump or immersion?

Bit of a strange setup here. Its a rented flat I have lived here 8yrs. We have a central heating system so the hot water comes off a combi boiler... a very large one at that.

The central heating is on at set times for the whole house (victorian converted house into flats) on a morning 6.00-8am and on an evening 5-10.30pm.

Problem is outside of these times no heating at all, and if like me u work shifts and nights you have to use electric heaters.

We were struggling to heat one room with a fan heater and that was keeping doors closed and costing a fortune as were also on £1 meter too for that so get charged a fortune for electric.

I got the units cheap, as I plan to stay here a while I only had to pay for it to be installed really as the units will come with me when I move its an investment for me really.

Below my lounge is a cold empty cellar which is freezing cold, it is so cold the carpet is cold and the room temp can drop to 10C in the night in here so it works well to keep the room warm for me. I also use it for cooling in the summer, due to working nights not able to sleep with windows open (ground floor flat) and noisy main road also.

At the moment I am getting an air off temp of 38C off the lounge unit, it has reached set point so it will pump in air at 38C and fluctuate that to meet the heat loss of the room.

So if it starts to realise the room temp is dropping or going to high it will speed up and pump more or less heat into the room at a diff temperature.

richardc1983

clockworks wrote: »

Richard

Thanks for the pics, Never seen the wall mount units before. What do you use for hot water? Heat pump or immersion?

Has your engineer been back to fix yet?

clockworks_2

Providing the courier makes it through the snow with the new part he will be back tonight to install. He was at the flat last night taking off the old part.

I'm a little surprised that ducted systems aren't that popular in the UK. I think they're more popular in the US. I know you don't have as much control for individual rooms but for small flats etc they're ideal. Take up no wall space and just a small duct in the ceiling. You would't notice it's there.

richardc1983

The thing is the ducted systems in the US are built at the time of building the house usually and are primarily used for air con.

I know someone in the US who has ducted for air con and in winter when they use the heating the system does not heat well as the grilles dont push the heat down so it stays at ceiling level.

How are you keeping warm at the mo clockworks?

clockworks_2

At the moment staying at mum's as i have caught a bug which has left me feeling pretty bad , but have an electric oil heater there but only have the 1 so can only heat one room at a time.

stevehead

richardc1983 wrote: »

I know someone in the US who has ducted for air con and in winter when they use the heating the system does not heat well as the grilles dont push the heat down so it stays at ceiling level.

I think this is the biggest failing in the current crop of standard air-to-air ASHPs. The designers still insist on high level indoor units; ideal for cooling as the cold air falls to where humans live. But for heating - dumb or what? OK my aircon shoves hot air downwards and relies on turbulence to mix it all up, but why not have a skirting board level air output? Surely the ideal would be something like yours Rich, with the hot air emanating from the bottom of the unit?

The only reason I can see for having a high up heater is that the indoor heat exchanger has to be very bulky for high efficiency. I've thought about ways to mount mine low down, but it would be a very large obstacle at floor level. Maybe one day I'll stick it in the fire place or summit.

richardc1983

Your units would be no good mounted low down Steve neither would any wall unit that has discharge from the bottom, in cooling the cold air would be directed straight across at you as you know it sends it across the ceiling and the cold air being heavier falls to floor level and blankets the room.

Heating it forces it down to the floor and does a good job of doing so.

My units one is like your steve so works the same and the other 2 are floor mounted but the air comes out the top so the flap points at an angle toweards the floor and does a good job.

There are many split units that are mounted at ceiling level take the cassette unit for example: The unit pictured is in cooling mode but in heating the air outlets round the sides point to the floor and due to the high powered fan, do a great job of heating and floors get evenly heated.

You would think the ducted units would invent some sort of air grille that has automatic louvres that when in heating point down to the floor. A lot of the grilles have manual adjustable louvres but users wont bother to change them and the air velocity from the grilles is not powerful enough to force the hot air down to lower levels even if they was so they have to rely on the room filling up with heat from ceiling down.