Heat Pumps and 10mm Microbore Piping

[Plumb]

Its a well known formula in the process industry

Obviously it's an equation I use on a daily basis I thought it looked familiar ,Ah well see if I can trawl the net for more useless information or perhaps stick pins in my eyes probably the latter seems a more attractive proposition

 

[MisterB]

I have just received the quote for my air to air heat pump, just under £1,300 plus VAT. I have not as yet worked out the payback period but if gas does double in price it should be a reasonable time. I have a choice of 1 unit or 2 units but there's not a great saving getting 2 so I will just get one for now. I have experience of these in an office situation but I'm not sure how noisy it will be in a home environment. If it all goes wrong at least I will gain air-con in our south facing living room.

The Ex-Gasman

I picked up four last year from eBay. All were gassed up and working. I had one fitted at home, I need two to be fitted in our caravans in France and am looking to have the last one installed somewhere at home, when I've worked out the best place for it.

I paid no more than £250 to buy each one, so your cost is a lot to pay just to 'try it'. Have a look for pre loved, you can often view them working before arranging to have them removed and reinstalled. Pipework shouldn't cost more than £90 and you can do the prep work yourself in terms of siting and installing pipework and cables but NOT installation on the refrigerant side (as you will be aware)

Just set a search on eBay for a unit. I have a contact in London who removed them from time to time and sells them on if you're interested?

We have 2.5kw units but you can get bigger ones, though the inside unit is around 1m long!!

This is ours in our conservatory. We wanted floor mounted, not wall mounted.

 

[EuroTrotters]

These are the ones I fit. This is our Daughters conservatory. But I am going to get the wire hidden.

Daikin Inverter with Wifi App and Google Play/Alexa Etc

 

[MisterB]

EuroTrotters

Is that a split unit with refrigerant gas? Looks nice. I've seen some all in one through the wall units, but they seem really big.

What price are they? I like the WiFi option. Ours has a remote, pretty easy to control

 

[EuroTrotters]

The Ex-Gasman

I picked up four last year from eBay. All were gassed up and working. I had one fitted at home, I need two to be fitted in our caravans in France and am looking to have the last one installed somewhere at home, when I've worked out the best place for it.

I paid no more than £250 to buy each one, so your cost is a lot to pay just to 'try it'. Have a look for pre loved, you can often view them working before arranging to have them removed and reinstalled. Pipework shouldn't cost more than £90 and you can do the prep work yourself in terms of siting and installing pipework and cables but NOT installation on the refrigerant side (as you will be aware)

Just set a search on eBay for a unit. I have a contact in London who removed them from time to time and sells them on if you're interested?

We have 2.5kw units but you can get bigger ones, though the inside unit is around 1m long!!View attachment 581444

This is ours in our conservatory. We wanted floor mounted, not wall mounted.

Great Price

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[EuroTrotters]

EuroTrotters

Is that a split unit with refrigerant gas? Looks nice. I've seen some all in one through the wall units, but they seem really big.

What price are they? I like the WiFi option. Ours has a remote, pretty easy to control

Pricey, but worth it if you cannot get bargains like you shown.

 

[gus-lopez]

I have just received the quote for my air to air heat pump, just under £1,300 plus VAT. I have not as yet worked out the payback period but if gas does double in price it should be a reasonable time. I have a choice of 1 unit or 2 units but there's not a great saving getting 2 so I will just get one for now. I have experience of these in an office situation but I'm not sure how noisy it will be in a home environment. If it all goes wrong at least I will gain air-con in our south facing living room.

Is that supplied & fitted?

 

[Odd-no-more]

Is that supplied & fitted?

Yes on the wall and working, I just have to put in a power supply and luckily there's a spare bay in the consumer unit.

 

[Richard n Ann]

Our Mitsubishi Electric 3.5kw floor mounted air conditioning system (trendy new name is air to air )was about £900 in 2009 just to buy (Mitsi never gave us more than about 5% discount off list )
You can buy wall mounts for less than half that...
Anyway.. removed the back radiator and fitted it myself in about 2 hours, it's coming into it's own now, since the price rises I've turned the gas boiler thermostat down to 17c and the smart meter is saying the cost of gas and electric per day is on average just under 4 quid

Edit: And the living room is toasty warm

 

[MisterB]

Air2Air is the most effective air source heat pump, but it makes me wonder why the original domestic hot air systems were so bad?

for anyone looking for a good deal (The Ex-Gasman ?)

<Broken link removed>

i would have considered making an offer on this if i didnt have an inverter already installed. i prefer floor mounted models as opposed to wall mounted. as we have quantum storage heaters throughout the rest of the house, it looks similar in size and appearance to one of the quantums.

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[Richard n Ann]

Just beware of Mitsubishi Heavy Industries, they are a different cheaper company to Mitsubishi Electric and use the Mitsubishi brand.

We had warranty problems with their indoor units developing refrigerant leaks.

Stick with Mitsubishi Electric or Daikin and you'll be ok

 

[Odd-no-more]

The unit I have been offered is a Fujitsu, I only received the quote yesterday and need to do some research on it. It has a COP of over 4 and looks ok, but I will read all the literature before I decide.

 

[MisterB]

The unit I have been offered is a Fujitsu, I only received the quote yesterday and need to do some research on it. It has a COP of over 4 and looks ok, but I will read all the literature before I decide.

The one fitted in our house is a Fujitsu, and it's been really good.

 

[EuroTrotters]

The one fitted in our house is a Fujitsu, and it's been really good.

If anyone is interested, I have an old R22 Fujitsu.

It’s about 20 years old, I removed it as we need more powerful heating.

Still working condition, would suit a small/medium size bedroom, great for the two week heatwave. Or maybe heat/dehumidify a small workshop.

Outside unit is very tatty old looking. But still works.

£50 collected . It’s Got R22 gas in I could probably sell for that.

Also a large high wall mounted unit, Panasonic. Case on the indoor is very brittle and broken as it was used in a conservatory. £95

I also have two more modern units in Spain . 10 years old. €75 each

 

[Richard n Ann]

The unit I have been offered is a Fujitsu, I only received the quote yesterday and need to do some research on it. It has a COP of over 4 and looks ok, but I will read all the literature before I decide.

I used to fit them for a company we sub contracted to. They're OK. Sometimes hard to work on, I remember changing a fan on one indoor unit and it had to come off the wall . We installed a good few brands trying to find a cheap good unit but always went back to Mitsubishi Electric or Daikin.

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[Jimbohorlicks]

This might be a daft question.
For the outside unit that relies on extracting heat from the air ,why are these units not housed in a small green house that would invariably be warmer than inside the glass than outside.?

 

[gpat]

This might be a daft question.
For the outside unit that relies on extracting heat from the air ,why are these units not housed in a small green house that would invariably be warmer than inside the glass than outside.?

Its not a daft question but it could be a conundrum I guess

The heat you feel in a greenhouse is mainly radiated heat through the glass. If you started to cool the air by fitting an outside unit then the air would cool very quickly wouldn't it. The actual total amount of heat energy in the air in the greenhouse is probably very low.

Also the efficiency of the system is not wholly dependant upon the outside air temperature, This is because degrees Centigrade is not a true scale. The real measure of temperature is degrees kelvin. Real (absolute) zero (0K) is -273C.

So whilst 10 degrees to 20 degrees C might seem like a big change in temperature (100%), in the real world of physical chemistry its only a tiny change (0.03%) and therefore there is only a marginal benefit.

 

[Jimbohorlicks]

Thanks for that gpat but it's still 10 degrees higher than outside the greenhouse whether it's Deg C or Deg K.
You say that the efficiency of the system is not wholly dependant on the outside air temperature.,I see that, but surely any increase in outside temperature would result in faster evaporation of the coolants inside the exchanger and therefore make it more efficient?

We have a small conservatory at the back of the house ,it's in the sun in the morning but not in the afternoon. But it's still reasonably pleasant in the afternoon at this time of year., A few degrees makes all the difference.and have often thought of pumping the warmer air from the conservatory into the house via a solar powered fan. Hence my original question

 

[gpat]

Thanks for that gpat but it's still 10 degrees higher than outside the greenhouse whether it's Deg C or Deg K.
You say that the efficiency of the system is not wholly dependant on the outside air temperature.,I see that, but surely any increase in outside temperature would result in faster evaporation of the coolants inside the exchanger and therefore make it more efficient?

We have a small conservatory at the back of the house ,it's in the sun in the morning but not in the afternoon. But it's still reasonably pleasant in the afternoon at this time of year., A few degrees makes all the difference.and have often thought of pumping the warmer air from the conservatory into the house via a solar powered fan. Hence my original question

Hi Jimbohorlicks . I think you are missing my point. Yes, but when you talk in degrees C sounds more than it really is

Degrees Kelvin is the true scale and going from 283K to 293K is tiny. In chemical/thermodynamic equations K is always used as C is just a manipulated scale to make life more straightforward when we talk about the weather.

Yes it would have the benefit you say, but its is only relatively small. Yes there is warm air in your conservatory and I am not denying that. What I am saying is that the thermal mass of that air is small and it is only transient. Consider what happens when the sun goes down. Your conservatory will cool down as quickly as it warms up. Heat transfer systems are used and yes you could pump that air into colder areas. Don't expect massive benefits through

 

[MisterB]

This might be a daft question.
For the outside unit that relies on extracting heat from the air ,why are these units not housed in a small green house that would invariably be warmer than inside the glass than outside.?

Ive always thought that aswell, but convinced myself that the cold air being pumped back out after the heat is extracted, might actually make it colder than the outside temp eventually. As these systems have been around a long time, I'm sure it would have been implemented by now if it was feasible.

As for recirculating warm air from your conservatory with a simple fan, I have seen it on TV where the warm air is brought down to floor level, but not sure how efficient it actually was?

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[gpat]

Ive always thought that aswell, but convinced myself that the cold air being pumped back out after the heat is extracted, might actually make it colder than the outside temp eventually. Very quickly

You are correct with small amendment

 

[Richard n Ann]

This might be a daft question.
For the outside unit that relies on extracting heat from the air ,why are these units not housed in a small green house that would invariably be warmer than inside the glass than outside.?

If the greenhouse was big enough it would work well. Consider that greenhouses are similar to conservatories which we've worked with a lot installing AC to cool, and...
We always say to customers whatever size ac you have in the conservatory, it won't cool it much in the summer, the heat gain from the sun is massive, the outdoor unit will be loaded up, high back pressure and will be blasting the heat out. Pity it's usually wasted. VRV systems don't waste it but that's a whole other area

Variable refrigerant flow - Wikipedia

en.m.wikipedia.org

 

[gpat]

If the greenhouse was big enough it would work well. Consider that greenhouses are similar to conservatories which we've worked with a lot installing AC to cool, and...
We always say to customers whatever size ac you have in the conservatory, it won't cool it much in the summer, the heat gain from the sun is massive, the outdoor unit will be loaded up, high back pressure and will be blasting the heat out. Pity it's usually wasted. VRV systems don't waste it but that's a whole other area

Variable refrigerant flow - Wikipedia

en.m.wikipedia.org

Im sorry. I'm not sure that is right either. Yes there is heat and in a big green house even more. However if you try to cool it with an air conditioning unit it appears that there is little effect. However it's an illusion. The air is cooled very quickly but at the same time is replaced with a radiated effect. You feel the radiant heat of the sun whatever the outside temperature. Bit like skiing at -10 in the Alps and feeling hot when sitting at the café.

It's a hard thing to get one's head around. If the sun shone constantly I would agree, but it rarely does, and the minute it goes the heat is gone.

Like I have said, I don't deny there is heat but the original question is why we don't put the evaporator bit of ashps in the greenhouse and the answer stands . There is little benefit.

 

[Richard n Ann]

Im sorry. I'm not sure that is right either. Yes there is heat and in a big green house even more. However if you try to cool it with an air conditioning unit it appears that there is little effect. However it's an illusion. The air is cooled very quickly but at the same time is replaced with a radiated effect. You feel the radiant heat of the sun whatever the outside temperature. Bit like skiing at -10 in the Alps and feeling hot when sitting at the café.

It's a hard thing to get one's head around. If the sun shone constantly I would agree, but it rarely does, and the minute it goes the heat is gone.

Like I have said, I don't deny there is heat but the original question is why we don't put the evaporator bit of ashps in the greenhouse and the answer stands . There is little benefit.

Yeah I should have said "it will work well if it's sunny all the time"