geothermal heating which one

weston1

have decided to go for geothermal heating system for new build circa 4000sq foot, with horizontal piping in garden. down to 2 systems which have some differences and need help. one system is a direct expansion system (heliotherm) which has refrigeration gas in pipes rather than water-antifreeze mix(worcestor bosch). the heliotherm system promises better cop of 5.6 as opposed to 4.2, but i tend to not overly rely on promises. can anyone tell me which type of system is best and why. tks.

heinbloed

Contact an independant heating engineer.
COPs are useless. Ask for a guaranteed seasonal efficiency, a guaranteed anual efficiency and a guaranteed maximum consumption of electric energy.
All calculated according to EN standards.

Check the maintenance costs, of course: guaranteed.

No problem for a competent person.
Cowboys shy away when confronted with written contracts!

creedp

heinbloed wrote: »

Contact an independant heating engineer.
COPs are useless. Ask for a guaranteed seasonal efficiency, a guaranteed anual efficiency and a guaranteed maximum consumption of electric energy.
All calculated according to EN standards.

Check the maintenance costs, of course: guaranteed.

No problem for a competent person.
Cowboys shy away when confronted with written contracts!

By the way OP, if you decide not to go down the HP route and are considering other sources of heat, please apply same the rigourous assessment regime as recommended here to all options. I don't think there are any systems out there that don't require maintenance and it should be easy to get a guaranteed maintance cost schedule for these options also. Definitely make sure the suppliers give you a guarantee of the maximum fuel costs for each option, irrespective of the severity of the weather you might experience over the lifetime of the system.

heinbloed

http://www.iee-cense.eu/upload/sites/iee-cense/external%20website/list%20of%20cen%20standards%20to%20support%20the%20epbd.pdf



@ creedp:

Fuel costs can not be guaranteed, ask your broker. He would be a billionair if he knows how that is done.....

@ the OP:

One can get a guarantee for the fuel consumption, that's basic standard. This guarantee is based on EN standards(see link above) and on local heating degree days.

The spare parts guarantee and maintenance contract is done via the manufacturer of the HP. Installers come and go.....

If a bog standard condensing boiler fails and the investment is lost €500-1,000 are written off.

If a borehole HP fails some €10,000-20,000 are to be written off.

Now ask the car manufacturer about the fuel consumption and you'll get a 'water proof' answer. Ask the leasing company for the guaranteed costs of a x-year contract - it will be answered.

If a €500-1,000 bicycle fails the expectations - bad luck, the money lost. But if the car fails - worse luck !

Therefore the EU offers and demands energy consumption guarantees. But you have to ask for them, the HP installers usually claim that this extra work isn't worth the expenses - if he admits that something like does exist at all....
Acredited installers will get the calculation done by the HP manufacturer, a computer programm does this in less than a minute once fed with the relevant data.

The EU demands (and Ireland as well !) that subsidised HPs are equipped with meters, giving an energy consumption (electricity-) reading.
Insist on another, extra meter to be installed (installed by the manufacturer, warranty !) at the point of thermal delivery - in the house - to read the amount of thermal energy actually delivered.
With these two numbers (kWh electricity versus kWh thermal energy) you have a water proof case, in case.

Only the high quality manufacturers offer this. The others fear confrontation with reality.


Contact a heating engineer, an energy advisor, a civil engineer for more detailed answers.
Incompetent sellers are the only ones who should not be relied on. Unless a third party insurance backs their claims, everything in writing of course.

As with the car purchase:ask a competent and independant advisor. And read the contract.

creedp

Fuel costs can not be guaranteed, ask your broker. He would be a billionair if he knows how that is done.....

The spare parts guarantee and maintenance contract is done via the manufacturer of the HP. Installers come and go.....

Exactly and all I was saying earlier this applies to all heating options.

If a bog standard condensing boiler fails and the investment is lost €500-1,000 are written off.

If a borehole HP fails some €10,000-20,000 are to be written off.

Come On now I know we all like supporting our own argument but€500 for a bog std condensor boiler versus €20,000 for a heat pump - there a credibility problem with this statement. I can only assume the boiler is heating a ckicken coop while the HP is heating a mansion!

Now ask the car manufacturer about the fuel consumption and you'll get a 'water proof' answer. Ask the leasing company for the guaranteed costs of a x-year contract - it will be answered.

Oh I know he'll swear his car will get 65mpg (old money) accorrding to some EU std but in reality you'll struggle to get 50mpg unless all your journey's are downhill with the wind at your back! As for the leasing company being able to tell you what your repayments will be Im not sure how this furthers the discussion!

If a €500-1,000 bicycle fails the expectations - bad luck, the money lost. But if the car fails - worse luck !

Here was I thinking that warranties were the norm these days whether it be on a bicycle or a car. Also if a product fails to meet what would be considered normal performance stds then I think the Sale of Gods Act should be called into play. Anyway what does 'fail' mean - never work, fail after a month, a year, 15 years?

As with the car purchase:ask a competent and independant advisor. And read the contract.

I fully agree with this statement and all I was saying is that apply the same approach to all options. To continue with your car analogy are you suggesting I would walk into a car showroom and throu down €20k for a cheap and cheerful Ford Focus. No I would do my research just as I would if I was throwing down €60k for a Mercedes.

All I was saying above is that all option need to be assessed using the same rigorous process.

The First Guru

Fully agree Heinblood.

HeinBloed As you are very good with information could you please do the following calculation for me???

Oil boiler is 90% Eff and Kerosene oil is 90 Cent per litre.

Heat pump has COP of 4 and electricity is 14 cent per Kw Hour.

Assuming both system are the same size I have two questions.

1. Which system is cheaper to run

2. What Coefficient of Performance does the heat pump need to equal the cost of the oil boiler?

Your answers would be greatly appreciated.

heinbloed

......could you please do the following calculation for me???

The 'calculation' you're proposing is idiotic. No joke, no insult.

Such a calculation doesn't exist in the heating industry. Because it does not compare the efficiency of the heating systems equipped with the two thermal sources.

A condensing boiler has an optimum efficiency at a certain parameter whilest a heat pump has this as well.

If the parameters change the efficiency of the systems change as well. Therefore the exact parameters have to be included in the energy balance of the thermal sources to be compared.
And these parameters are fluctuating, are dynamic.

A plain sample: if the external air temperature drops the fuel efficiency of the condensing boiler increases. The fuel(electricity, gas) efficiency of the air based HP drops under this circumstance.
But the output temperature (the flow temperature coming from the thermal source) has to be increased to cover the increased thermal demand of the building to be supplied.

And so on.


For economics the costs of the complete heating systems (not only their fuel's cost) have to be included as well. Over a certain length of time, years, decades.

Contact a heating engineer for a proper calculation. And pay him/her. Then you can expect an exact, repeatable calculation. Signed and guaranteed.

A precise calculation demands more than a COP of the heatpump. You have to give more information, better the copy of an independant test lab like Buchs in Switzerland.
He/she will also need details about the thermal distribution, the thermal loss of the building, the exact positioning of the building/HP/boiler, the heating degree days and occupation pattern/thermal demand and so on.


Any other calculation aproach is like reading the tea leafs.

heinbloed

Just saw this post:

http://www.boards.ie/vbulletin/showthread.php?t=2056272423

where apples are compared with pears. Some doing so claim to be fruit farmers, them can't be helped.