Score - Sustainable Construction in Rural and Fragile Areas for Energy efficiency

Guidelines for integrated territorial planning – Heat pump

“Smart house” is energetically provided with renewable energy sources. Solar energy is exploited also with greater solar collector’s installation for water preparation that heats facilities and other water requirements. Water is at lower temperatures in reservoir heated with heat pump, at peak time and by increased use with district wood biomass heating. So as an additional secondary heating system we use heat pump type water-water. Brand of the heat pump is Termotechnik model VV 13/15 E1. As a heat source is used underground water trough pumping it within the evaporator of the heat pump using submersible pump. In the evaporator underground water transmits heat and cooled water for proximately 3 to 4 °C
returns back. The heat pump achieves very high level of efficiency. Before purchasing and installation is necessary to check the availability of underground water and the temperature of the water. Temperature of the underground water can not be lower then 7 °C
(in our case the temperature of underground water is 14 °C), required is minimum flow of 0, 2 m³/h for 1 kW of heat power (in our case, the flow is 3, 4 m³/h). Due to the higher heating number are recommended low-temperature heating systems in our case the heating is in walls and floor.

Next to the heating is also carried out passive cooling system of the facility. For cooling we have a system by which the cold source (ground water) is pumped trough an intermediate heat exchanger, which cools water for cooling facilities. Cooling of facilities is carried out with help of floor and wall piping system. Such system is effectively reduced, because we can not allowed temperature water in piping system to go below + 18 ° C to avoid condensation of floor and wall surface. For calm cooling trough walls and floors are available two passive cooling stations PA SIV 6 R and PA SIV 10 R, which prevents the cooling water to drop temperature below the dew point.

• Digital display of heating system display (outdoor temperature, temperature of return, water temperature in boiler, operating mode…)
• Managing heating system based on a temperature of outdoor  air for  optimum performance of a system and for maximizing savings
• The possibility of direct control up to 3 direct branches + sanitary water, possibility of automatic control of additional source (boiler, electric heater …)

Indication for the Bio-construction Action Plan

• It is our opinion that the biggest obstacle to even greater use of heat pumps represents high initial investment costs compared to the other heat sources for heating system, despite the fact that further more the costs are lower.
• Granting the irreversible funds and easier method to access then is one of the solutions. Countries that have this kind of heat pump co-financing regulated, record bigger use of such heating system. Meanwhile in Slovenia we record annual battle with bureaucracy for the irreversible funds.

Possible criteria for MED bio-housing quality certificate

• Heat pumps apply to the international standards EN 225 and EN 14511. Some submit the coefficient of performance (COP), using old standard EN 255, which takes into account heated water temperature difference of 10 K, while the standard EN 14511 takes into account the temperature difference of 5 K. Parameter difference is by this comparison of COP up to 10 %.
• Standard EN 14511does not specify minimum performance criteria for heat pumps, it only defines the standard test conditions (source temperature and heat sink) for different types of heat pumps (air/water, solution (air)/water, water/water, etc).
• It makes sense to impose certain requirements about achieving the minimum performance criteria of heat pumps for the customer confidence.

Case studies

−       Bistra hiša - Smart house (Martjanci, Slovenia)

Download PDF (Slovenian language)