How my Heat Pump was operating in winter 2007/2008

Here I’m describing shortly how my heat pump was operating last winter 2007/2008, what were the temperatures, what were the costs and other parameters.
An average temperature in year 2007 was around 12 degrees Celsius – Slovenia, central location (this temperature is above average for our location). The winter 2007/2008 was not so cold but lower temperatures lasted quite long time. Here is the data what was happening in heating season 2007/2008:

• We switched on heating in September 24th 2007 and was stopped in May 10th 2008. The heating season lasted 229 days.
• Heat pump was operating 680 hours (approximately 3 hours per day on average)
• Total costs of operating for the whole season were 230 EUR (2550 kWh) - 1 Euro per day.
• Minimum outer temperature was -9.9 degrees Celsius. This peak requested heat pump to run 4,5 hours per day.
• Room temperatures were from 20 – 21 degrees Celsius (night temperatures around 19)
• Temperatures of medium from vertical collector to Heat Pump were from 7 (coldest days) to 12 degrees Celsius (at the start and end of season).
• Temperatures of water in floor heating were adjusted from 26 up to 30 degrees Celsius (talking for returning line – water temperature coming from floor heating back to the Heat Pump).
  
  No maintenance was needed, no problems, just paying bills for electricity :-) I just switched on the heat pump in September and switched it off in May. If anybody has similar experience or totally different please add a comment. Thank you for reading and supporting this page.

Installing Heat Pump and Water Heater

My Heat Pump does not have all needed installation integrated (pumps, valves, expansion…) – it is not “Plug’n’Play” like someone from computer science would say. So the next step was preparing installation schema for external installations (pipes, pumps, wires, heat exchanger and water heater). Luckily I have some background on that subject so it was quite easy for me to prepare all schemas. At that time (2005) not many plumbers in our country have knowledge and skills to install heat pump … so learning again J. Nowadays many plumbers have required knowledge and skills. Here is the photo of already installed Heat Pump and Water Heater with all needed parts that enable heating and cooling. If somebody is interested in detailed installation schema please add your comment bellow with your opinion what do you think about this blog and don’t forget to add your e-mail and preferred language of the schema (currently: Slovenian, English). I will send the schema to you.
Coming next: How my heat pump is operating?

Buying a Heat Pump

Outer collector and pipe installations were already finished and it was time to select and buy the heart of the system, so called Heat pump. In Europe we have from 5 to maximum 10 well known and high quality heat pump production companies. I was investigating many of them and after that decided to buy a quality product from my country. When buying a heat pump you should be careful what to buy. You should consider many options:

• Do you plan to use the heat pump only for heating or also for hot water


• Do you plan to use a heat pump also for cooling the house during summer


• Do you prefer active (needs reversible heat pump) or passive cooling (less energy used for cooling)


• Do you prefer a product out of the box (this kind of heat pump already includes automatics, electric connections, pumps, valves, and also boiler) or do you prefer only bare heat pump with basic regulation and security automatics (you will have to install some parts additionally)

And most important: don’t forget to calculate carefully how much power you will need for heating the house. I have bought the heat pump with output power of 14kW, input power 3,1kW. It has a scroll compressor. It also has additional pipe heater of 6 kW for extremely cold winters (I didn’t use it so far). You can see the heat pump on the photo.

Geothermal Heat Pump Project LOGO!

I have created new LOGO for my Heat Pump Project Blog. Hope you like it. Thank you for supporting my Blog.

Connecting and Testing Vertical Collector for the Heat Pump

The first photo is showing a testing procedure for vertical collector. Each vertical collector should be tested before connected to the heat pump. It is very small possibility of leaking, but you must be 100% sure. Testing is accomplished with water and a water pump (hand driven) which can produce a pressure up to 5 bar. Pressure meter must be stable at least 1 hour – 1 hour the same pressure.

The second photo is showing pipes already connecting vertical collector and heat pump. There is a 0,75 to 1 meter deep channel where pipes are placed.

Pipes for Geothermal Collector

Pipes for geothermal collector are very important part of heat pump system. For 100 meters of vertical geothermal collector that is inserted into drilled hole, we usually need 400 meters of strong pipes (2 pipe loops inserted in one hole). If we calculate the water pressure at the end of 100 meters collector (100 meters deep under the surface) we get 10 bars (1 bar / 10 meters). We must add another 2 bars to get optimal working conditions for the heat pump. That is way pipes must be strong and must stand at least 12 bars of pressure for 100 meters collector. We have used 16 bar pipes (32mm in diameter, 3 mm wall thickness, PE 100, SIST EN 12201) from Slovene (Europe) producer.

Drilling the hole, close-up

This is a close-up photo of drilling the hole for my heat pump project. Parallel to drilling we have chosen pipes for vertical geothermal collector. Special pipes were used. We have used more than 1000 meters.