Air Source heat Pump

akaPABLO01

Member
Its just finding an really good way of siting the pipework in , or under the muck ,without wrecking it all afterwards, when the mucks done its heating ?
Probably a few people have tried it :)
Thoughts I had are similar to a cylinder except instead of internal coils have wrap around container coils. I expect the heat to be very low grade though. What is the internal temp of manure stacked in say a volume of a 40,000 litre tank for example? My estimate is that it would need a temperature of at least 60/70°. The transfer of heat from a solid? To a liquid would see a huge temperature loss?
 
I was thinking more of an array like the type you use in lakes and such . Dont know if thats feasible?
I have been thinking of an open loop GSHP system from a flowing body of open water 100 yds away , here at home , mainly pumping the water through constantly (4 gallons a minute approx .)

Anyroad , its never going to happen
 

akaPABLO01

Member
I was thinking more of an array like the type you use in lakes and such . Dont know if thats feasible?
I have been thinking of an open loop GSHP system from a flowing body of open water 100 yds away , here at home , mainly pumping the water through constantly (4 gallons a minute approx .)

Anyroad , its never going to happen
Maybe a drying floor concept. What needs to be understood is that pumps only require 5° of any scale temp as long as it’s above minus, compressors do the rest. The concept is achievable though.
 

Frankzy

Member
Location
Jamtland, Sweden
ASHP's are quite popular in Sweden even up here in the north since they are comparatively cheap and provides a noticeably better efficiency than direct heating even down to -20.
With that said though most people nowadays are switching to geothermal heat pumps which pretty much always manage a 4 to 5 times efficiency gain over direct heating..
 

anemoi power

New Member
Air source heat pumps work perfectly fine in new build homes with high insulation and modern building methods! if not they will cost you a fortune to operate in winter months! they also are not really suited to the Northern English climate which is damp and unpredictable
 

Dave645

Member
Arable Farmer
Location
N Lincs
Air source heat pumps work perfectly fine in new build homes with high insulation and modern building methods! if not they will cost you a fortune to operate in winter months! they also are not really suited to the Northern English climate which is damp and unpredictable
Both types of heat pump ground and air are good, but the delivery of that heat is also a factor, well insulated homes work well because the operating temperature in the delivery system is low, my water temp in my underfloor heating rarely goes over 30c, so it’s vey efficient it’s actually 5 star rated that’s due to the design of the delivery system my underfloor heating, If I had tried radiators and tried to imitated the heating style of an oil boiler where I ramp up my heating rapidly so require very hot water to flow rapidly I would have a rubbish system, as heat pumps like to provide low temps at high efficiency and high temps at low efficiency.
My heating when on runs 24/7 it measures the return temp of the water from the underfloor heating and with the use of a heat curve and an outside temp gauge, runs my heating no room stats or other tech. My pumps run on low settings and as the rooms cool they effect the water temp and the heat pump runs to top it up as needed. Using just the heat pumps controller.

My ground temps have never been below freezing. So my return water has never been below freezing either, in 7 years.

If you have a large heat load then what ever you run it on it will be expensive but if you have a large heat load with a heat pump you need a great delivery system to get the best from them.
My house is not passive rated, but it either is or could be, I rarely turn the heating on until November (it’s not yet on this year and I haven’t lit any fires either). The passive heat my house creates from cooking, etc, and solar gain from windows can cover a lot of my heating, the heat pump only gets turned on for heating because I don’t light a fire every day, when it really gets cold, and it’s just a 5kw wood burner in my living room it’s no boiler stove.

Another big win are heat recovery units that and good air tightness, mine result was a 1 which was the best my council had ever tested you need below 10 to pass building regs in 2012, the next nearest was a 1 room flat, which got 1.1 (mine was a 300m2 three story detached house.)
 

Exfarmer

Member
Location
Bury St Edmunds
Both types of heat pump ground and air are good, but the delivery of that heat is also a factor, well insulated homes work well because the operating temperature in the delivery system is low, my water temp in my underfloor heating rarely goes over 30c, so it’s vey efficient it’s actually 5 star rated that’s due to the design of the delivery system my underfloor heating, If I had tried radiators and tried to imitated the heating style of an oil boiler where I ramp up my heating rapidly so require very hot water to flow rapidly I would have a rubbish system, as heat pumps like to provide low temps at high efficiency and high temps at low efficiency.
My heating when on runs 24/7 it measures the return temp of the water from the underfloor heating and with the use of a heat curve and an outside temp gauge, runs my heating no room stats or other tech. My pumps run on low settings and as the rooms cool they effect the water temp and the heat pump runs to top it up as needed. Using just the heat pumps controller.

My ground temps have never been below freezing. So my return water has never been below freezing either, in 7 years.

If you have a large heat load then what ever you run it on it will be expensive but if you have a large heat load with a heat pump you need a great delivery system to get the best from them.
My house is not passive rated, but it either is or could be, I rarely turn the heating on until November (it’s not yet on this year and I haven’t lit any fires either). The passive heat my house creates from cooking, etc, and solar gain from windows can cover a lot of my heating, the heat pump only gets turned on for heating because I don’t light a fire every day, when it really gets cold, and it’s just a 5kw wood burner in my living room it’s no boiler stove.

Another big win are heat recovery units that and good air tightness, mine result was a 1 which was the best my council had ever tested you need below 10 to pass building regs in 2012, the next nearest was a 1 room flat, which got 1.1 (mine was a 300m2 three story detached house.)
Great if you like stuffy air. I personally like to keep windows open and have fresh air in the house , for which there is a price.
All houses should have an air to air heat exchanger fitted
 

renewablejohn

Member
Location
lancs
Great if you like stuffy air. I personally like to keep windows open and have fresh air in the house , for which there is a price.
All houses should have an air to air heat exchanger fitted

Dont have opening windows all well sealed but never stuffy thanks to an effective MVHR system.
 
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Dave645

Member
Arable Farmer
Location
N Lincs
Great if you like stuffy air. I personally like to keep windows open and have fresh air in the house , for which there is a price.
All houses should have an air to air heat exchanger fitted
I agree a Heat recovery system is a must for air tight houses, which I have ;) I get nice cooled air in summer and warmed air in winter via a ground pipe installed in the inlet in the heat recovery system it’s lovely, it replaces all the air every 2 hours about twice as fast as is needed to avoid a stuffy house. And the air is filtered so no flies reduced dust. As it’s extracting dust from the house and delivering filtered fresh air 24/7. The cost of running it is more than covered by the heat load it saves.

Open windows are a very expensive solution as you say, especially in winter, an open window will increase your heat load for the entire house by large amounts, I can keep my bedroom cool without an open window I just reduce flow to our bedroom underfloor system.
if you cannot fit a whole house system, like I have it’s more than possible to fit small scale systems like bathroom extractors heat recovery units, where you think you may need it, you get the same volume of fresh air you just don’t loses the heat from it, you can cut the 100% loss of an open window, to only about an 10-20% loss, with a heat recovery extractor.
If you take a average house with the needed fresh air of one entire air change for the volume of your house every 4 hours as a minimum, basically your dumping all the heat out of your house every 4 hours with the external air temp that’s outside including when it’s below freezing, so every 4 hours you have to fully reheat your house.

Ok a case study, If externally the air temp is 0 C
In my house incoming air is heated by the soil temperature, so it never dips below 10 C the air leaving my house is at around 22C I lose 5-10% of that difference, so I lose 0.6-1.2 C every 2 hours and I exchange the entire volume of my house with fresh air, while an open window loses on a cold night 22C in 4 hours for the entire volume of the house.
If your ventilating at the minimum recommended so 11 C in the same 2 hours as me with half as good standard of ventilation. Or the full 22 C in the same 2 hours if you ventilate as well as I do.

I think I know which system will have big heating bills.

When we look at heating we have to look at the entire system not just heating, but trickle vents are the biggest waste of money, why bother insulating if your only going to just let it escape via trickle vents.
Retro fitting a heat recovery system into lofts make far more sense. One can very simply be installed in most lofts, where you will struggle is for ground floor if you have a 2 story house but there are some clever options to even do this.
Heat recovery units normal extract from wet rooms and deliver the clean filtered air to living and bed rooms. If your going for a well insulated home heat recovery is a big saver.
 

Exfarmer

Member
Location
Bury St Edmunds
The problem thoufgh surelly, is these systems are very difficult to retro fit. I did look at heat exchangers a while back but the reality it seemed to me was a huge amount of work to the house. GSHP is obviously another option requiring major landscape surgery and the space. I am aware of complaints that the energy used running such systems can be very high, but I suspect may be largely poor deign
 

Dave645

Member
Arable Farmer
Location
N Lincs
The problem thoufgh surelly, is these systems are very difficult to retro fit. I did look at heat exchangers a while back but the reality it seemed to me was a huge amount of work to the house. GSHP is obviously another option requiring major landscape surgery and the space. I am aware of complaints that the energy used running such systems can be very high, but I suspect may be largely poor deign
Your correct second floor if you have access to a loft is not too hard, ground floors are more work.
https://www.zehnder.co.uk/
I used this companies unit it’s was head and shoulders above the competition at the time I was looking around at home building shows.
they have some intresting flat ducting now designed for retro fitting or so I have been told.
With a claimed 95% efficiency and I can tell you, there units are great, especaly if you add a ground pipe,
https://www.rehau.com/gb-en/homeowners/ground-air-heat-exchanger-erth-tubes

I designed my house using info I found on websites like

https://www.greenbuildingstore.co.uk/
Look at their case studies
I found a great heating engineer that design my underfloor heating system and worked with me on the heating design,
http://www.jknrenewables.co.uk
It’s basically using close centres to maximise emitter efficiency with underfloor heating.
He actualy lives in my village.

If your gutting a house it’s a great place to start from but you still need to be carful ducting for heat recovery units needs planning fully out on the how your going to actually accommodate The ducting.
If the house has high ceilings it’s possible that you create a false ceiling to run the ducts around under an existing floor.
I used open web joists the ones with metal in them, but if I did it again I would go concrete joists and a false ceiling they are just rock solid floors. And thinner.
Air tightness is about details it doesn’t cost much extra to do but you need to be mindful at every stage of the build as some things are easy to do at some stages but harder to do later.
Floor joists is a good point if you rap the ends by putting a small bit of air membrane under them into the cavity then installing the joists and block work that between them, then bring it up over them and back into the house during construction of the rest of the wall, and tape the joints you avoid siliconing the floor joist into the block work pockets they sit in. Which can be done but takes far more time and effort.
 

renewablejohn

Member
Location
lancs
The problem thoufgh surelly, is these systems are very difficult to retro fit. I did look at heat exchangers a while back but the reality it seemed to me was a huge amount of work to the house. GSHP is obviously another option requiring major landscape surgery and the space. I am aware of complaints that the energy used running such systems can be very high, but I suspect may be largely poor deign

Its no longer difficult to retrofit with modern systems. I used Lunos e2 in our 17th Century grade 2 listed farmhouse. Each level of the farmhouse required a Lunos e2 unit which is actually a pair which work in tandem with each other so as one extracts the other blows fresh air into the house. The hardest part was drilling the 4 inch holes through 2 foot thick of solid stone but with the appropriate drill and diamond holesaw it was relatively easy. Energy usage is minimal with each unit similar to a computer fan. It was a requirement of my Listed building consent as it protects the fabric of the building by removing condensation and maintaining a stable temperature.
 

Dave645

Member
Arable Farmer
Location
N Lincs
Electricity ££££££££££££ my friend has a refrigeration business doing nicely removing these things.
Electricity bills are down to heat load and delivery systems, my house is 300m2 over 3 floors, with high ceilings so a lot of volume, my entire electric bill is for 10,000 units this has been the average for the last 7 years, I don’t pull out the non heating and hot water demand that just for everything including washing and tumble drying for 4 people with 2 teenagers in that mix, dishwasher etc that’s an average of 27 units per day at 14p/unit, or about £116 per month, I could reduce that by lighting my wood burning stove more than the 5-10 times a year I do, but that’s cost over conveniance on my part.

If the system is efficient a GSHP can do 1-4 or better one unit of electric give 4 plus units of heat.

Ok oil can deliver about 13.67 kWh of energy minus boiler efficiency losses.

Oil is 46p per litre you can get electric for around 11p per unit from buying groups and you can get cheap night rate deals at 5p/kWh
So do the maths

46p dived by 11p equals 4.181 we times that by the efficiency of the GSHP can be 5-1 so we take that 4.181 time the 5 we get 20.90kwh of energy for your 46p of oil.
So cost is efficiency times by the price of you electric verses the oil price.
The oil delivers only 13.67kwh of energy max that minus the boiler efficiency losses.
Verses the heat pump efficiency times the unit price of electric.
Which if you take an efficient system well installed can deliver 5-1 so you can get more energy for your money.

If I had a high demand house I would have installed a wood burning stove with a back boiler to run my system as the primary and the heat pump with a thermal store as the automatic side. That way I could maximise my ability to reduce my bills with wood. Which I get for free.

So yes system design is key.
 

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