Because the main man dont like them because they use energy all be it to produce more or sane some they still use energy. I think this is why?

Just to clarify its was also because of the enormous number of threads associated with heat pumps (over 60)... so always search before you post and add to another thread.

J

perhaps it because there being wrongly sold in the UK as the answer to low carbon/energy space heating
when really reducing heat load would not only make more sense, its also probably the cheaper option
unfortunately ,cheap simple solutions and profit dont normal go hand in hand

Mark , that would be interesting , my address is on my account info. thanks

bot de paille.

"GET IN" you are a legend.

Mark

Mark,

Could you sketch out the the benefits of ASHP vs GSHP please as this seems to be a key issue ?

J

My e-mail account is on my profile.

I do advise people on the return on investment (both financialy and environmentaly) on the return on investment on different options; taking a independent and objective view considering the immediate benefits and the whole life cycle of a building.

The UK government is sufficient concerned with the mis-selling of heat pumps to have stated that further reseach is required (hence the reason for MANDATORY government performance values in new homes).

Untill a proper system for predicting seasonaly adjusted performance can be set up then this will not change and even then a rigourous, building regulation approved, design and comissioning system will be required. Untill then no manufacturers claims can be accepted for new homes.

This approach may, of course, stifle innovation, but is necessary - a home has a huge environmental impact and we a a long way short of where we need to be in rectifying this.

exactly! while innovation and emerging tech do have a very valid place in the discussion, we do need to focus more on passive solutions and reducing our demand - more efficient appliances running on a hybrid of systems depending on primary use and location. there is so much good tech out there that putting together a decent system is not hard. the main obstacle is availability and price, but that is only because we aren't designing for it in the mainstream.

Posted By: Mark PainterWhy are we not allowed to consider air source heat pumps as they generate over 4 to 5 times the amount of energy they consume???? Is this not renewable re using the heat in the air???

Comments please

??? Not allowed to talk about them???

I've seen dozens of threads and have contributed to several.

Problem to me seems to be that even the best performing ones - do less than the 4 to 5 times you mention at the time you need the heat the most ie.e when it's below 5 degrees. In a well insualted home, over a heating season they can save CO2 and money, but when it's really cold you're best to switch off the heat pump and switch to gas. This is becuase they have a COP of 2 at this temperature. Seasonal performance is therefore usually worked out as 2.5 to factor in most of the heat you demand is drwan at the coldest time of year. The 4 to 5 times is best possible - i.e when it's 15 degrees outside, which hopefully means you'll be using next to no heating anyway.

If you use a heat pump during peak electric periods in the middle of winter, say the time you return to the house and want to warm it up, you'll be using electricity from a peak load combine cycle gas turbine powerstation which means you are burning gas to get electricity at an efficincy of 60%. And then paying 15p / kwH for the electricity. On carbon, £ and resource depletion terms you'd be better off burning the gas in a 90% efficient gas boilier and paying 4p kWh for the priveledge.

It get compicated as it gets warmer. At some point between 5 and 15 degrees - and depending on your tariff, and carbon mix from your supplier the numbers can stack in favour of the heat pump.

So the best solution seems to be to have both!

Posted By: PaulTDantez - a stated aim of the Passiv Haus institute is to reduce domestic heating demand to the point where Germany has enough biomass energy to heat their homes.

I do not accept heat pumps are inevitable

Paul, I haven't seen this aim of the PHI before. Can you give me a pointer to where they state it?

I am surprised by it, but I confess that I was also surprised when I realized that Feist supported the use of heat pumps. You can see that support on this page for example - http://www.passivhaustagung.de/Passive_House_E/compact_system_passive_house.htm - and on that page he also says "The German biomass potential (some 90 Billion kWh/a at maximum) is sufficient to cover 16% of the contemporary heating requirement of all households. If the efficiency of the buildings is increased to the level of passive houses (i.e. a factor 5), the same energy will be sufficient to heat 79% of all domestic buildings." That's why I'm surprised to hear of their 100% biomass statement.

I agree with you that large reductions in energy demand are absolutely necessary. We also need lots of renewable energy sources and most probably we need nuclear too. And a miracle.

Mark, it reads like a bunch of marketing BS.
For credibility you need real numbers; i.e. what is the COP at -10C outside heating domestic hot water to 60C?
Here's a spec sheet from a FHP water-water unit. Don't bother telling me what your product MAY do, tell me what it WILL do.

<blockquote><cite>Posted By: ralphd</cite>Mark, it reads like a bunch of marketing BS.
For credibility you need real numbers; i.e. what is the COP at -10C outside heating domestic hot water to 60C?
Here's a spec sheet from a FHP water-water unit. Don't bother telling me what your product MAY do, tell me what it WILL do.</blockquote>

Ralph

Can provide the graphs on this information but as for the COP at minus ten we have not had it tested to that extreme as we don't generally get that sort of temperature in this country very often but i will go away and have an answer for you tomorrow as my other computer at work has the graphs on and i cannot paste on here. I can e-mail the info tomorrow if you want so send an email but the info i do have is only the cop of unit at 45 degrees but the units comply with all relevant European standards, including EN14511- both in terms of operating efficiency and manufacturing process as our manufacturing facilities are ISO 9001 accredited. The units have a COP of 3.24 based upon testing against the criteria set out in EN14511 - based upon an ambient temperature of 1/2 degrees C (rather than 6/7—meaning that the units are extremely efficient) and use R407c refrigerant.

I will look into your question tomorrow but when we where testing we never has that temperature outside so i will see if i can extrapolate the data and see what the coldest temp we had and what it was performing like. I think off top of my head the temp went down to minus 7 but as for temperature in cylinder i don't think it got up to 60 degrees. But you need to look at the cylinder also as this is a thermal store and adds to the system. the calculations my partner did today were suggesting the cylinder added another 2.44 Kw of energy to the system but i will ask tomorrow. If you email me your address i can provide all the information on the ashp cop as i have a powerpoint presentation that has all the graphs on. And it also compares our propery with another used by BRE as a generic model using gas combi.

Mark

Mark,

I'm not interested in your product. I'm pointing out that other products have detailed performance specs at various source/load temps.
A 3.24 COP is pretty good for an air-source heat pump. Geothermal pumps (like the FHP spec sheet I sent) are much better. Here's another geothermal manufacturer to compare.
http://www.nordicghp.com/mg/

R290 performs better at most load/source temperatures than R407c, and is really green (enough for greenpeace, at least).
http://archive.greenpeace.org/ozone/greenfreeze/

Well it is quite interesting to note that France, a country that has been very forward in it's green energy initiatives (offering tax cashbacks to anyone that installed green heating equipment), WAS offering up to 50% off heat pumps.

For 2009, they made some changes and air/air heat pumps have been dropped completely, i.e. 0% off, whereas ground source heat pumps remain at 50%. This for me is very telling, as clearly, someone within the French government thinks that air/air heat pumps should not be encouraged, and this in a country where nearly all the electricity is produced by nuclear, i.e. no C02 emissions. If it were by gas, then presumably they would have dropped them even quicker.

For anyone interested, condensing oil/gas boilers get 30% off I think, double glazing 25%, insulation 50%, wood boilers 40%.

Posted By: bot de paille While millions of people tap into Google without considering the environment, a typical search generates about 7g of CO2 Boiling a kettle generates about 15g.

Very unfair to pick on Google though. What they fail to mention is the amount of CO that would be produced if we didn't have the internet to help us.