Sizing geothermia and buffer storage tank with GSHP

kabe

Hi!

What do you think about installing a little (or not so little) buffer tank fitted to a floor heating system? The heat pump is a geothermal one. Some people tell me it's not neccesary if I oversize the floor heating (i.e. by reducing the distance between pipes to 8-10 cm). It perhaps makes sense, because the water in the pipes can be considered itself as a little "lung" that works like a buffer tank, doesn't it?

On the other hand in Spain, where I live, GSHPs are not well known yet, and installers lack background, in particular about correct sizing the system. For example, my new house is 190 m2, has 2 floors and is located in northern Spain, a really cold region. I will get it well insulated (I hope so, the architect is my girl's brother!), with no swimming pool and with no solar panels. I've been given a range of pumps from 8 kW to 18 kW! What is your experience ?

Here the most common GSHPs are NIBE, Thermia, Stibel-Eltron (Sweden) and Hautec (Germany). By the way, boreholes cost about 35-45€/m.

Thx!

heinbloed

The investment you're planning seems to be a waste of money. Spain has excellent subsidies to solar thermal heating as well as experienced plumbers for the job.Get a real energy demand assesment done, a family "architect" might not be the right person to do so. An energy advisor will also have the details on how to get the most oout of an investment. As far as I know Spain demands a min. installation of renewable energy in every new build of 10%, local authorities frequently demand more coverage.I don't know if heatpumps are considered as renewable, I doubt it.Using electric energy to create heat that has to be stored to make use of it is about the most uneconomic way to use energy.Similar to night storage heaters.Contact the European Solar Thermal Platform for their Spanish partners, they'll point you the way to go for renewable technology. Spain is THE country to install an economical solar thermal system.Only to be matched by Malta , Sicily and Cyprus and parts of Greece.

kabe

Thanks, heinbloed, for your answer, but you should get better information before being so categorical about something you don`t know: Spain is not only sun and the Mediteranean! In the northern part, where I live (-10º, -4º in winter and maximun 32º in the summer, which, by the way, lasts only 2 months) it's COMPLETLY UNECONOMIC to install a solar thermal system: solar radiation is the lowest in all the country and NOBODY uses it for heating, only for sanitary uses. Belive me, I know what I´m talking about, I am not so stupid I don´t like wasting my money either! Besides geothermic heatpumps are considered as renewable in Spain, and are subsidized about 30%-40% the total cost.

Now I would be very grateful If someone might answer to my question :rolleyes:.

Thx.

heinbloed wrote: »

The investment you're planning seems to be a waste of money. Spain has excellent subsidies to solar thermal heating as well as experienced plumbers for the job.Get a real energy demand assesment done, a family "architect" might not be the right person to do so. An energy advisor will also have the details on how to get the most oout of an investment. As far as I know Spain demands a min. installation of renewable energy in every new build of 10%, local authorities frequently demand more coverage.I don't know if heatpumps are considered as renewable, I doubt it.Using electric energy to create heat that has to be stored to make use of it is about the most uneconomic way to use energy.Similar to night storage heaters.Contact the European Solar Thermal Platform for their Spanish partners, they'll point you the way to go for renewable technology. Spain is THE country to install an economical solar thermal system.Only to be matched by Malta , Sicily and Cyprus and parts of Greece.

Chimpster

kabe wrote: »

Besides geothermic heatpumps are considered as renewable in Spain, and are subsidized about 30%-40% the total cost.

Now I would be very grateful If someone might answer to my question :rolleyes:.

Thx.

What efficiency is electricity produced at in northern spain? These needs to be taken into account when considering if its renewable or not.

NIBE has one of the highest COP's on the market (Independent Test Results) so you prob wont go too far wrong with them.

The only way you can size you heat pump is get an independent heat demand calculation done for the house first your heat pump can then be sized from this. As for a buffer tank well a good heating engineer would answer this but I would have thought that a properly sized buffer tank would lead to a more efficient heating system.

heinbloed

To kabe:I live in Ireland with much lower temperatures as you have described and a much lower amount of winter sunshine then in any part of Spain. But I'm heating my house with solar energy. I think you don't know much about renewables at all. How high is the energy demand of your new build ? Is the family architect not able to sort that out? Is your interest not there? It's a legal demand all over the EU to have that sorted out before the building starts.Solar heating works without electricity input from the powerplant, without CO2 emissions and without radioactive pollution/poisoning of people as it frequently happens in Spain. A renewable source. If you think that the outdated powerplants of Spain will be able to deliver "renewable" energy in the short term you're wrong there.The EU had to finance an oil powered de-salination plant for Almeria because the locals couldn't afford to build a powerplant.....this country has still a long way to go from Franco to modernity. The storing of energy costs energy, be it in a battery or in a watertank.There is nothing more wastefull then storing warm water made with the aid of electricity. But you wouldn't have to be an architect to know that.

kabe

heinbloed wrote: »

I think you don't know much about renewables at all.

Probably, but I feel lucky you know much more than me and illuminate all of my doubts with your great wisdom.

heinbloed wrote: »

Is the family architect not able to sort that out? Is your interest not there? It's a legal demand all over the EU to have that sorted out before the building starts.Solar heating works without electricity input from the powerplant, without CO2 emissions and without radioactive pollution/poisoning of people as it frequently happens in Spain. A renewable source. If you think that the outdated powerplants of Spain will be able to deliver "renewable" energy in the short term you're wrong there.The EU had to finance an oil powered de-salination plant for Almeria because the locals couldn't afford to build a powerplant.....this country has still a long way to go from Franco to modernity. The storing of energy costs energy, be it in a battery or in a watertank.There is nothing more wastefull then storing warm water made with the aid of electricity. But you wouldn't have to be an architect to know that.

It seems to me incredible how you feel so self-confident to pontificate on something (renewable energy policy in Spain, solar ratiation ratio in my region, 1000 km from Almeria!) or someone (me, my architect) you know nothing about. You´re talking through your hat. My post doesn't aim to discuss about CO2 emissions, poisoning of people or Franco (maybe it's the only thing you know right about Spain). My question was clear, and also my idea about energy efficiency, renewable sources and wasting my money. I'm afraid you got the wrong end of the stick, friend... Thank you anyway.