ASHP - Am I so unlucky?

[MikeJhn]

The problem with installing on an internal wall is the need for the condensation pipe from the internal unit, I did this on a garden office adjacent to my workshop with small bowl in the workshop, but not very attractive.

 

[johnb2713]

The problem with installing on an internal wall is the need for the condensation pipe from the internal unit, I did this on a garden office adjacent to my workshop with small bowl in the workshop, but not very attractive.

There are some very neat and tidy condensate pumps as mentioned earlier, on my kitchen unit shown here it’s actually in the trunking on th RH side. The condensate is pumped above the ceiling to exit through an outside wall.




This is the sort of thing that Ive used.

https://www.tradesparky.com/heating...UIYw6AILnEwF0s2CS_vWvk7gvGpd1CexoCwkcQAvD_BwE

 

[Geoff1946]

Thanks for that pump reference John. That might just change my mind about putting in a system. How is the pump controlled?

Reason I'm asking is that I had experience of such a system when I did a maintenance job. It comprised a peristaltic pump, much bigger than that, which used two temperature sensors in the indoor unit to determine when condensate was going to be produced. The whole thing was repeatedly unreliable. its failure usually resulting in water spillage. I certainly wouldn't welcome one in my home.

 

[johnb2713]

Thanks for that pump reference John. That might just change my mind about putting in a system. How is the pump controlled?

Reason I'm asking is that I had experience of such a system when I did a maintenance job. It comprised a peristaltic pump, much bigger than that, which used two temperature sensors in the indoor unit to determine when condensate was going to be produced. The whole thing was repeatedly unreliable. its failure usually resulting in water spillage. I certainly wouldn't welcome one in my home.

Its a reliable 'dumb' unit. simple timer operation, when it's on cooling mode condensate is pumped every 'x' minutes, there is a float switch too that triggers the pump if the level gets high.

 

[Flylead]

.. buy an air conditioner that does heating and cooling with much better efficiencies than the air to water heat pumps.... We have 14 of them in various parts of the house.... fast to respond unlike air to water which often needs bigger radiators to cope with the lower flow temperatures.

Thanks for all your information, really interesting.
I've never understood why, in the UK, we're obsessed with water as a heat transfer medium for ASHP systems. The water-store/pumps/controls/bigger radiators & pipework/ just adds and unnecessary layer of complexity and cost to the installation.
But, please can ask what might be a silly question: does each of your internal wall mounted unit have its own corresponding external unit or have you a multiplex distribution for refrigerant gas (dependant on the mode of operation) to wherever it's required? If separate units have you got them dotted around the outside walls or grouped together in an inconspicuous location?
How do you achieve your hot water requirement?
Thanks,

 

[johnb2713]

Thanks for all your information, really interesting.
I've never understood why, in the UK, we're obsessed with water as a heat transfer medium for ASHP systems. The water-store/pumps/controls/bigger radiators & pipework/ just adds and unnecessary layer of complexity and cost to the installation.

I suppose it goes back to earlier days when we had fires with back boilers

But, please can ask what might be a silly question: does each of your internal wall mounted unit have its own corresponding external unit or have you a multiplex distribution for refrigerant gas (dependant on the mode of operation) to wherever it's required?

At home theyre all individual 1 indoor unit and 1 outdoor unit. At my shop I have an outdoor unit that feeds 2 indoor units and another one that feed 4 indoor units.

If separate units have you got them dotted around the outside walls or grouped together in an inconspicuous location?

It was a case of finding convenient locations to tie up between the units. I have a cluster of 6 units on the west side of my house the other 8 units are in various locations.

How do you achieve your hot water requirement?
Thanks,

I use an immersion heater on off peak tariff.

 

[Geoff1946]

Its a reliable 'dumb' unit. simple timer operation, when it's on cooling mode condensate is pumped every 'x' minutes, there is a float switch too that triggers the pump if the level gets high.

You obviously trust it because if that goes wrong it will dump the condensate on your TV.

 

[MikeJhn]

Also be aware the external units have a large fan and could be a noise nuisance to your neighbours if located near a boundary, also some find the internal units are too noisy to sleep with, I have two, one for my garden office and one for the workshop, I would not consider a split unit in the house but would consider an external air conditioning unit feeding ductwork into a false ceiling, you need to hear one before putting one into a bedroom, some consider then very noisy others don't.

 

[MikeJhn]

I've never understood why, in the UK, we're obsessed with water as a heat transfer medium for ASHP systems. The water-store/pumps/controls/bigger radiators & pipework/ just adds and unnecessary layer of complexity and cost to the installation.

ASHP are only able to heat water too about 40 degrees, this is inadequate for a radiator installation unless the radiators are very big, but ideal for under floor heating, hence their popularity for new builds where the underfloor pipes and insulation can be laid during construction.

 

[Geoff1946]

Also be aware the external units have a large fan and could be a noise nuisance to your neighbours if located near a boundary, also some find the internal units are too noisy to sleep with, I have two, one for my garden office and one for the workshop, I would not consider a split unit in the house but would consider an external air conditioning unit feeding ductwork into a false ceiling, you need to hear one before putting one into a bedroom, some consider then very noisy others don't.

I agree with that. We have one in the Cyprus hotel room we visit. We tend to use it to cool the room during the evening then turn it off when going to bed. We can at a pinch sleep with it on low fan rate but I wouldn't call it silent.

 

[johnb2713]

Also be aware the external units have a large fan and could be a noise nuisance to your neighbours

They do have a large fan that turns very slowly which means very little noise.

if located near a boundary, also some find the internal units are too noisy to sleep with

The Mitsubishi ones we have are absolutely inaudible when running at slow speed. The slow speed is plenty fast enough to keep the room cool overnight. Remember when we had the 42 degC record temps? our bedroom was at a very nice 18 deg C with an absolutely silent AC unit

I have two, one for my garden office and one for the workshop, I would not consider a split unit in the house but would consider an external air conditioning unit feeding ductwork into a false ceiling, you need to hear one before putting one into a bedroom, some consider then very noisy others don't.

I would guess that some cheaper units could well be noisy, the Mitsubishi ones have inverter drives so the compressor doesnt start and stop with thud that many others do, the speed is modulated according to demand. I have just had a look on their website and here you can see what I'm talking about.



19 db(A), a library is 40, a conversation 60, a vac cleaner 80 etc, noise is NOT an issue with Mitsubishi units and I have 13 of them!

 

[johnb2713]

I agree with that. We have one in the Cyprus hotel room we visit. We tend to use it to cool the room during the evening then turn it off when going to bed. We can at a pinch sleep with it on low fan rate but I wouldn't call it silent.

Look at the spec of the mitsubishi units I'm talking about, 19 db(A) is inaudible.

 

[johnb2713]

ASHP are only able to heat water too about 40 degrees, this is inadequate for a radiator installation unless the radiators are very big, but ideal for under floor heating, hence their popularity for new builds where the underfloor pipes and insulation can be laid during construction.

Mitsubishi ECODAN air-water heatpumps run at 45 degC can elevate to 65 degC for hot water storage safety cycle.
I reduce our condensing boiler flow temperature down to 35 deg C last winter to trial operation at low flow temperatures. The house maintained the room temperatures without issue, the rads all standard sizes, conservatory underfloor wet heating. Turning the flow up to 45 deg C resulted in a faster response as expected but nothing else changed. Our house does have good insulation, it was built in 1990 by a very reputable builder who was known for quality work.

 

[johnb2713]

You obviously trust it because if that goes wrong it will dump the condensate on your TV.

Oh yes, it has a cut off switch if the level rises before it over flows but short of a pump failure, that wont happen. We did have a small leak from a power shower a few years ago




My other half had been going through some paperwork the night before, whilst we were out at work a copper to plastic pipe adapter fitting fractured. The pump sensing flow was quite happy to start pumping. We estimate it had been running for around 7 hours. Upstairs in the room above thye pressure built up in the wall and burst the wall, the coving neatly transported the water around the room. The TV got a very good soaking but amazingly still works to this day. Total repair bill £90,000, paid by insurance and the house was upside down and in a mess for 2 years whilst drying out etc took place followed by rebuilding.
So, no, a condensate pump doesnt give me cause for concern

 

[bladerunnerpv]

oh my ! What a nightmare to come home to and then to live through for ages afterwards. 2yrs!

We all grumble about the cost of insurance, but it's times like that which make it worth every penny.

Note to self - check the stop cock hasn't seized up again and can be turned off!

 

[Geoff1946]

Same thing happened to a friend of mine and wrecked his new kitchen..
I just don't do plastic plumbing, except wastes and flexible tap connectors, the latter which I've never seen catastrophically fail.
All mine is good old fashioned solid copper. A bit more expensive to install but it gives me peace of mind.

 

[johnb2713]

Same thing happened to a friend of mine and wrecked his new kitchen..

Aye, the water went down under the floor, travelled along the concrete base and then backup over the whole ground floor. The mess, the smell was just unbelievable. Quite how people go on when rivers flood their homes I dont know, |I literally felt our house would never get back to normal, thankfully it did and whilst it cost us dearly the end result is superb.

I just don't do plastic plumbing, except wastes and flexible tap connectors, the latter which I've never seen catastrophically fail.
All mine is good old fashioned solid copper. A bit more expensive to install but it gives me peace of mind.

Me too, this part was installed by a bathroom company some 10 years earlier.

 

[Badger]

Touch wood, they do seem very good, I have about 4 left to do to become all Mitsubishi units. The efficiency is amazing, I've seen -8 deg C outside and still theyre pumping the heat out with very little energy being consumed. I've just managed to pick up a 7.5 kW unit with ceiling mounted cassette, it's only been installed for 3 months, £500, absolute bargain and will sort out my shop heating and cooling.

Hi John how big have you made your battery bank system to support over night use on electric

 

[johnb2713]

Hi John how big have you made your battery bank system to support over night use on electric

Initially I had 7kWh with my solar install and then added my DIY 14kWh battery. That ran the whole house no problem at all. I wanted to be doubly sure moving my heating across to Air to Air heat pumps that I could sustain that in the coldest of conditions, I'd like to get rid of gas completely. I have added another 14kWh of EVE cells to my system and now I don't need to worry at all, it copes with everything. I'm now trying to develop the software with home assistant to take control of my charging, if the weather next day is good it will charge a little, if its brilliant it wont charge at all etc saving of grid off peak energy consumption.

 

[bladerunnerpv]

I have added another 14kWh of EVE cells to my system

Blimey, you don't do things by halves do you! Did you need another multiplus too, or is all 28kWh connected to the one unit? Another Seplos BMS ?

Bear with me, I'm a slow learner, how long would all that take to charge ?

Assuming supply is coming in through a 63A fuse, then 230V x 63A is ~14.5kW, so less than 2h to fully charge the lot if need be? No. It needs to go from 230V AC to ~48V DC first, which is the inverters job.

So the multiplus 5kVA unit has continuous output power of 5000VA or 4000W, so that would make it 28hWh / 4000w = 7hrs?

It quotes max charge current of 70A.
Or the absorption voltage is 57.5V * min(70A,63A) = 3.62kW, so 28hWh / 3.62kW = 7.7hrs?