Heat pumps and domestic hot water

[unguided1]

Having looked through a number of MIs why do heatpump manufacturers still insist that an external heatpump is acceptible for domestic hot water, its certainly not the way I do it.

So how do you guys keep efficiency to a maximum on your external heatpump and still produce domestic hot water cheaply.
Discuss

 

[poorman]

So what you are saying is that your installers have installed a heat pump to do your heating and domestic hot water and to do the domestic hot water it is in fact working outside its parameters therefore costing you as a customer more money to run than it should and also that in the winter they are hoping that every day is a sunny day for the solar thermal??

The link was just to show the Nibe Fighter2015 they are not the company that installed it and I have no connection with them, their website shows all the nibe airsource heaters, if I'd put nibes website on you would have to download pdfs for the same info.
We are still waiting for our installer to get back, he's on holiday. As its set up it uses the immerser along with the airsource to heat the water to 55deg which I thought it wouldn't have to do if the outside temp is 18+degs, as I said we are waiting our installers return to see what he says.
There seems to be a lot of mis-information, if thats the word, floating about regarding airsource heating, some saying that they are quite capable of heating DHW and others saying that they cannot. Today was a hot sunny day and the solar boosted the hot water, for a time, up to nearly 55deg but without the immerser on two showers and its back to 43degs. The f2015 runs at the most for less than five minutes at a time, always, is that normal? As for the solar in winter I doubt very much if it will produce much hot water at all, for more than three months we don't get sun on the house, bloody big mountaun in the way.

 

[quality]

5 mins at a time , no thats not normal

 

[ecowarm]

Poor installation if you have a large mountain blocking the sun in the winter?????

 

[poorman]

We live in the west of scotland, short daylight for about 4 months of the year, last couple of winters we saw temps down to -14, but it has to be clear at night for that, most of the time it's cloudy and not to cold.
We have a nibe f2015 8.5kw feeding a 285ltr tank, 120 CH,145 HW and 20 SP, linked to 8 radiators, 3 have thermostaic valves. The nibe control is a smo 5 (cut down for UK market?) with danfoss TP5000i room stat (fitted in hall).
Nibe have said its okay to turn immerser off and the put the smo5 to manual and turn off the CH.
Doing this we get error 16 short operations time and occasionally error 6 tripped high pressure pressostat. I have contacted nibe a couple of times and they are really helpful, but its down to the installers to sort once he gets back off his holidays. The system has only been installed for 90 days so hopefully its just teething problems.
The wife says that we should have kept the storage heaters and the large HWT, 185ltrs at 65degs, enough for a grown family of 5.

 

[CES]

The link was just to show the Nibe Fighter2015 they are not the company that installed it and I have no connection with them, their website shows all the nibe airsource heaters, if I'd put nibes website on you would have to download pdfs for the same info.
We are still waiting for our installer to get back, he's on holiday. As its set up it uses the immerser along with the airsource to heat the water to 55deg which I thought it wouldn't have to do if the outside temp is 18+degs, as I said we are waiting our installers return to see what he says.
There seems to be a lot of mis-information, if thats the word, floating about regarding airsource heating, some saying that they are quite capable of heating DHW and others saying that they cannot. Today was a hot sunny day and the solar boosted the hot water, for a time, up to nearly 55deg but without the immerser on two showers and its back to 43degs. The f2015 runs at the most for less than five minutes at a time, always, is that normal? As for the solar in winter I doubt very much if it will produce much hot water at all, for more than three months we don't get sun on the house, bloody big mountaun in the way.

Sounds to me your f2015 has not been sized correctly if it only runs 5 mins at a time.

 

[core heating]

regarding using ASHP for hot water with immersion to top up the temperature etc.. i do my installs totally diferent to this.

i use ASHP purely for the heating. thus keeping the unit happily within its parameters and keeping the cop as high as possible. ( as we all know these do not like trying to warm water to 55or above if the air outside is -3 for eg. ) they are good but not magicians

for the hot water side of things i use a completely independant unit which had no wiring or pipe interlink with the ASHP thus enabling the mcs acceditation.. this unit is a mains pressurised hot water cylinder with a micro ASHP on the top of it.

it draws warm air ( pref from bathrooms which is often warm and damp) to heat the water. it uses a 650watt unit and provides 3.25kw of heat into the water.

the glorious thing about this kit is its byproduct is chilled air. usually we duct this to a bedroom or to outside via a diverter box in attec.

so in summer free air cooling when unit is running if you wish. we set unit to store water at 52degrees then once a week at midnight the immersion kicks in and takes unit to 65 for the legonella removal.

also the reason i prefer this system over using the main ASHP to warming hot water is in the summer months your saving money by not starting up a 6 or 8 kw unit or what ever size to do a cylinder of water

 

[ecowarm]

what make is the hot water heat pump unit?

 

[core heating]

its called "ecosent" unit from ESP. never had a problem with them

 

[core heating]

just been onyour website (very good by the way) and your already aware of the system

 

[poorman]

At last we have solved the problem with this setup, simple, so simple that even the installers overlooked it. The inline filter was blocked, why dunno will check again next week. We now have a rather warm house. Tahnks for all those that took the trouble to reply.