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

 

[quality]

Are you talkin air source I presume

 

[unguided1]

Are you talkin air source I presume

Sorry Quality, a very good point yes I do mean air source

 

[quality]

I would like to query the same myself if I maySo your not alone

 

[unguided1]

In my eyes the fact that manufacturers claim that theyre units can do domestic hot water completely goes against EN14511 which is the standard that all manufacturers have to meet to be MCS accredited products, but if they advertise there units as doing domestic hot water this means that their units will always be working out of parameter

 

[ecowarm]

Just found this on Danfoss web site Q&A about there ashp

Will it provide enough hot water for baths showers & domestic hot water?

With the correct design and equipment, all domestic hot water requirements would be provided by the air source or ground source heat pump throughout the year. Heat pumps produce water at a lower temperature than boiler systems. Instead of water that may be scalding water produced is hot enough for all normal domestic requirements. You will notice that you do not have to add as much cold water to your baths and showers. The aim is to save money and energy with either an air source or ground source system. There is no point in taking water to temperatures that can't be used anyway (above 55°C).



WOW no point in preventing[h=1]Legionella ????????[/h] then

 

[markfxy]

I read of one the other day that claimed up to 80° cant remember which one but they didnt mention COP when reaching those temperatures!.. I have always recommended Solar thermal and economy 7 to compliment any heat pump wether its air source or ground source

 

[fergie656]

I've also found that if you shop about you can get a good electric rate per kw. I fit alot of daikin altherma and found that econemy 10 works well on that

 

[CES]

Ecodans heat up to 55oC, but they have an immersion heater built into the tanks in their packaged units to bring the temp up to 65 for legionella prevention. This is usually done on a timer during the night on a cheap rate economy 10 or 7 or whatever.

 

[Kev the gas]

When I enquired about having cheap rate electricity my supplier said if I changed to that tariff then my Day rate price per KW would increase !!

Kev.

 

[eaton]

set up the last one fro hw at 50c and use an immersion to top up to 65c at midnight, 10c wont cost a great deal and was included in the running cost per year, have a tmv off the unvented set at 45c so 50c from the heat pump is spot on, heat pump heats a buffer first.

 

[unguided1]

Amazing, the fact that heatpumps cost more to run at higher temperatures and yet they are being installed to run at temperatures that make them uneconomical just makes no sence to me especially when the heatpump will already be working hard in the depths of winter, Also in my eyes a heatpump that has been designed with a back immersion heater in it has only been designed to work well in certain parameters to attain EN1411 and therefore should not be an MCS accredited unit.
So you thoughts again

 

[fergie656]

I've done a heat pump that goes upto 80 degrees, cracking peice of kit. But if radiators and underfloor heating is sized correctly, and the heat pump is sized correctly, and the correct tarrif is setup on the electric meter then the running cost's will be far lower than lpg or oil. I was speaking to a customer today who i installed a heat pump into there 3 bedroom bungalow, married couple 2 young kids, they have worked out that average heating and hot water bills has been 10 pound a week over the year, and thats with temperatures dropping down to -15 in the winter

 

[unguided1]

I've done a heat pump that goes upto 80 degrees, cracking peice of kit. But if radiators and underfloor heating is sized correctly, and the heat pump is sized correctly, and the correct tarrif is setup on the electric meter then the running cost's will be far lower than lpg or oil. I was speaking to a customer today who i installed a heat pump into there 3 bedroom bungalow, married couple 2 young kids, they have worked out that average heating and hot water bills has been 10 pound a week over the year, and thats with temperatures dropping down to -15 in the winter

I assume thats a high temp one then

 

[fergie656]

Yeah daikin altherma HT, Impressive bit of kit

 

[unguided1]

I bet its expensive as well

 

[eaton]

what cop at 80c is that operating at, i cant see how that is efficient

 

[fergie656]

After 65 degrees the cop drops off to between 2 and 3, also the outdoor units can operate down to -27

 

[unguided1]

Ive not dealt with the Daikin HT unit yet is it a water connection or a refrigerant connection between the external and internal unit

 

[ecowarm]

Dakin use an external unit and the second stage heat pump is internal which takes it up to 80c

It uses refrigerant pipe work between the two units

It is supposed to give COP of over 3

 

[ecowarm]

This is the best info I can find [DLMURL]http://www.ecobuild.co.uk/var/uploads/exhibitor/2206/rfkpw9zltw.pdf[/DLMURL]

 

[poorman]

we've got a nibe 2015 docked to hot water cylinder. 146ltrs hot water, 120 central heating and 20 ltrs solar. The way it has been set up the pump uses the immerser as well as the air source. If we switch the immerser off we get between 50-60 litres of water at 43deg from the air source(tonight). If the sun shines (wot) the solar will take the temp up to about 50-52deg. Nibe say that the f2015 should heat the 146ltrs to around 50+ without the solar or immerser.
We went from 185ltr at 65deg water tank that cost during last years summer, 72p to heat, total daily electric less that £2.00 to this summer over £3.50 daily and inadequate hot water, if we leave the system on auto, thats using immerser and air source. We have never had the heating on during the months May to October but with this system on auto we get warm radiators and on one occasion the house was at 25deg, phew. We are awaiting the installers return visit with trepidation

NIBE F2015 can both heat hot
water effectively at high outdoor temperatures and give a high output
to the heating system at low outdoor temperatures

 

[poorman]

Air Source Heat Pump Installer - Solo Heating Installations; Air Source Heat Pump Installers
Air Source Heat Pumps also provide hot water up to temperatures as high as 58°C which is suitable for all domestic and commercial requirements. This will require a tank which is specified to the usage of the homeowner or usage of the building. The larger the tank, the larger the output of water.

 

[ecowarm]

if we leave the system on auto, thats using immerser and air source. We have never had the heating on during the months May to October but with this system on auto we get warm radiators and on one occasion the house was at 25deg, phew. We are awaiting the installers return visit with trepidation


Why are you advertising this company if the system is not working correctly?????

 

[unguided1]

we've got a nibe 2015 docked to hot water cylinder. 146ltrs hot water, 120 central heating and 20 ltrs solar. The way it has been set up the pump uses the immerser as well as the air source. If we switch the immerser off we get between 50-60 litres of water at 43deg from the air source(tonight). If the sun shines (wot) the solar will take the temp up to about 50-52deg. Nibe say that the f2015 should heat the 146ltrs to around 50+ without the solar or immerser.
We went from 185ltr at 65deg water tank that cost during last years summer, 72p to heat, total daily electric less that £2.00 to this summer over £3.50 daily and inadequate hot water, if we leave the system on auto, thats using immerser and air source. We have never had the heating on during the months May to October but with this system on auto we get warm radiators and on one occasion the house was at 25deg, phew. We are awaiting the installers return visit with trepidation

NIBE F2015 can both heat hot
water effectively at high outdoor temperatures and give a high output
to the heating system at low outdoor temperatures

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??

 

[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.