Nibe Fighter 360p ashp costing me loads to run

richardc1983

A fire has a large output of heat it is also radiant heat so makes you feel warm regardless of the actual air temperature. People have complained of the cold draughts from the vents previously. An open fire is a very inefficient heat source this is supposed to be efficient.

John_Pierpoint

“You don't get owt for nowt“.
If we assume that the incoming air is heated from 5 degrees to 20 degrees and the outgoing air is cooled from 20 degrees to 0 degrees there is in reality not a lot of heat available in 5 degrees and an air change of say 2 - 3 per hour?. If condensation is dribbling out through a drain there is a bit of useful latent heat, just as there is with a condensing gas boiler.
However the healthy air movement makes the room feel colder and when the external temperature drops below zero we are back to the ice making machine problem. There has to be some sort of energy input into the building in addition the the small heat pump. Sweaty human bodies at say 120W each? Wide screen TV? Fridge? Cooking ? Surfing the net?
This might work in a "PassivHaus" but we are talking low cost housing association, build by the semi-literate.(I've been on building sites where the workers were all from the Ukraine).
http://en.wikipedia.org/wiki/Passive_house
Switching the kit on and off to try and get a better performance, is not what the designers expected.

jasonoldy69

richardc1983 wrote: »

But from a comfort perspective it should pre heat the incoming makeup that is how all the heat recovery systems work. Its backwards way and I would hate to be sat near those vents in the room when air at 0C or less is blowing in. So air at 0C when your sat in a room at 20C if you are lucky to get it that high is going to feel mighty cold. IN theory its a good idea but the reality is it just doesnt work and hasnt been designed properly.

With the outside air being just a few degrees lower than inside, is enough to bring a chill, when your sat near them vents.

Cardew

[QUOTE=John_Pierpoint;49884157 build by the semi-literate.(I've been on building sites where the workers were all from the Ukraine).
[/QUOTE]

Как вызов вы подразумевает работники для Украин iliterate

grahamc2003

John_Pierpoint wrote: »

“You don't get owt for nowt“.

(Your original text not in italics, my replies in italics)

If we assume that the incoming air is heated from 5 degrees to 20 degrees and the outgoing air is cooled from 20 degrees to 0 degrees there is in reality not a lot of heat available in 5 degrees and an air change of say 2 - 3 per hour?.

Well my numbers were just examples - no idea what the real numbers are typically. I just used them to illustrate that in theory these exhaust HPs can work, which I thought was being questioned.

But even so, in the above example, the only heat needed to be extracted from 5C to 0C is that to replace the heat loss through walls windows loft etc - which is why I initially stated they probably work in other countries due to much higher insulation standards.


If condensation is dribbling out through a drain there is a bit of useful latent heat, just as there is with a condensing gas boiler.
However the healthy air movement makes the room feel colder

As I said, I think that's a red herring (prepared to change my mind if there's some contrary evidence) with airflow probably less than people expect (and less than I initially expected a few months ago) and also well sited vents (probably behind rads, only in cooler rooms etc). The starting point for me is that these systems do work, in theory and in practice sometimes, so obviously the system won't blast freezing cold air at the settee in the living room).


and when the external temperature drops below zero we are back to the ice making machine problem.

Yeah, I expect that's correct. Imo, the icing will both be less than non-exhaust HPs (due to the highereair temp being blown over the evaporator), and the defrost strategy, if necessary, would be simple, with the 20c air quickly removing any ice, no reverse cycling or other fancy stuff necessary.

There has to be some sort of energy input into the building in addition the the small heat pump. Sweaty human bodies at say 120W each? Wide screen TV? Fridge? Cooking ? Surfing the net?

Yeah, there certainly will be that heat recovery (that's the basic idea isn't it? recover the heat while supplying fresh air ventilation?). So as you imply, in the heat balance, this contribution will be added to the heat from the cooling between 5 and 0 in my example, used to balance the house heat loss through walls etc. But this contribution won't, imv, be large e.g. most houses need heating above this background electricity use to keep warm (i.e. to balance the heat loss mentioned). Probably typically 300W to 500W for the small properties for which these HPs are designed?


Switching the kit on and off to try and get a better performance, is not what the designers expected.

I think that may well be one of the contributary factors to poor performance some on this thread unfortunately experience. Which is to be expected if the running costs are so large due to factors such as poor insulation, draughts entering noit through vents etc etc.

John_Pierpoint

I think we probably agree with each other:
Buildings not properly designed for the trickle heating of a heat pump.
Built by badly trained operatives who don't understand the significance of good sealing and avoidance of cold bridging.
Minimal commissioning of the heating and no proper training of the householder.
Householders who need to economise but don't understand how their heating system is intended to work.
The only graphs I have seen stress the advantages of under floor heating where the pump is set to tick over in the day time and really charge up the floor slab in the small hours of the morning when economy 7 rates are available and there cannot be any solar gain from the windows.
These tenants should have been given gas if it is available. They have not been given gas partly because the landlord is saving the costs of maintenance and the annual annual gas safe service and certificate.
In Danemark, as I understand it, city centre flats get combined heat and power. The suburbs get condensing gas boilers and the isolated properties in the countryside get ground source heat pumps.

I am not actually clear as to the delivery of the heat back into the rooms from the heat pump - I was guessing it was warm air.

lovesfarmbpha

http://www.eaem.co.uk/news/attack-energy-use-buildings-targets-heat-pumps

lovesfarmbpha

Tha facts are people that the NIBE 360p has a CoP of 2,6 (given by NIBE on the back page of the manual) also certifed at 2,6 by the BRE.....The CoP is in Lab perfect conditions so even if we did live in a lab then we would still be producing more CO2 than a gas system...fact....maths dont lie....I have been contacted by one of the board memebers of MCS who is keen to remove exahust air heat pumps from the MCS site....they will reclassify exhaust air heat pumps on the 16th January 2012...using the new EN standards ( all be it a year overdue).....if your connected to gas then these systems are pointless.....if your not connected to gas then they will reduce emmisions and cost however the NIBE system is propbably not the make I would suggest as there are plenty of better Exhaust air heat pumps on the market that far out perfom this product...it is mainly for Social housing landlords that want cheap..... The link above is in support of our complaint ...good bye NIBE nice try ................

lovesfarmbpha

Its actaully a shame the NIBE systems have caused such a stir as the onther manufaturers of Exhaust air heat pumps have been tared with the same brush.....excuses used to why this NIBE systems do not perform well....worst winter in 100 years...bad install..lack of user understanding...etc etc ...
Facts are facts ...maths are maths and unless you have a new mathematical system you would like to share with us then please accept the fact that exhaust air heat pumps are truly dead and buried...or soon to be...adios...this year and soon you will see these systems banished to the locker which contains the fodue set....grrrrrrrrrr rant over....

Cardew

lovesfarmbpha wrote: »

Its actaully a shame the NIBE systems have caused such a stir as the onther manufaturers of Exhaust air heat pumps have been tared with the same brush.....excuses used to why this NIBE systems do not perform well....worst winter in 100 years...bad install..lack of user understanding...etc etc ...
Facts are facts ...maths are maths and unless you have a new mathematical system you would like to share with us then please accept the fact that exhaust air heat pumps are truly dead and buried...or soon to be...adios...this year and soon you will see these systems banished to the locker which contains the fodue set....grrrrrrrrrr rant over....

It is not just exhaust ASHPs that are not performing. Both the link you gave, the EST trial report, and numerous reports on MSE and the Web make grim reading.

There really must be some way of pinning the reponsibilty on the manufacturers to ensure an installation works. At the moment all manufacturers sell their product kits to installers and take no further part in the deals. It is just pot luck for customers.

The other point is the complexity of the operating instructions. I read with some amusement the adjustments required on this system. My wife(with a Masters degree - so she ain't thick) just wouldn't cope and I am sure that applies to the majority.