Project Results
Demonstration and integration
ZBK demo site, Kraków, Poland
The RESHeat demo site is made for a multi-residential building located in ul. Działkowa in Cracow, Poland. The building is owned by the Municipal Buildings Management Board in Kraków.
The Działkowa estate is a relatively new settlement of four residential buildings put into use in June 2013. All buildings have central heating and domestic hot water systems powered by gas boilers – each building has a separate boiler room.
One of the buildings was chosen for the RESHeat system integration and demonstration. The building chosen is located in ul. Działkowa 26 and is a multi-family building with 24 appartments, with a total usable area of over 1,190 m2. Next to the chosen building, there are three almost identical buildings, built simultaneously and with the same technology.
The heating demand of the building is 105.14 MWh/year.
ZBK demo site in cracow, poland
ZBK Demo Site - Main components of the RESHeat system
- 8 sun-tracking PTC (Parabolic trough) solar collectors;
- 68 stationary PV modules with a power output of 29.92 kW peak;
- 2 sun-tracking Photovoltaic/Thermal (PV/T) systems, each consisting of 12 PV modules and a cooling system at their rear side;
- RE 76 heat pump with a maximum heating capacity of 95 kW;
- 2 buffer tanks with capacities of 500 L and 750 L with 2 immersed heat exchangers. The 750 L with immersed heat exchanger buffer tank is used as a domestic hot water tank supplier, and the 500 L buffer tank without heat exchanger is used for central heating;
- 1 insulated underground heat storage tank with a capacity of 50 m3 and immersed heat exchanger; 15 vertical ground heat exchangers, each 100 m deep;
- 4 heat exchangers.
The concept design of the RESHeat system for the ZBK demo site
ZBK Demo Site - Stationary PV modules
In the ZBK demo site, 68 PV modules, each with a peak power output of 440 W, are installed on the roof of the building. The maximum power output of the PV system is 29.92 kW.
Firstly, the roof of the building was prepared by installing the racks for the PV modules. After the installation of the rack system, PV modules are installed on the roof of the building, and the electrical connections are completed.
Once the connections on the roof are completed, the connection of the output of the PV system to the inverter is arranged. The cables are connected through the side of the building as the electrical box for the building was located in that section.
A 30 kW inverter was chosen to connect the output of the PV system. A similar approach is followed as in the Limanowa demo site. The generated electricity is consumed by the RESHeat system components, and the excess electricity is sold to the grid.
The pV rack, completed stationary PV system and inverter For The ZBK Demo Site
ZBK Demo Site - Sun-Tracking PTC Collectors
The sun-tracking parabolic trough collectors are used to generate thermal energy to cover the domestic hot water demand in the ZBK demo site building.
8 sun-tracking solar collectors are used to generate thermal energy with a peak of 30.4 kW. A water/glycol (35 %) mixture is used as the working fluid. The heat from the solar collectors is fed into a 750 L buffer tank.
The bottom side inlet of the 750 L buffer tanks is connected to the cold water supply, and the top side is connected to the existing domestic hot water tank.
Another heat exchanger is placed between the 750 L tank and the existing domestic hot water tank. The hot side of the heat exchanger is connected to the load side of the heat pump. The cold of the heat exchanger is fed from the water from the 750 L buffer tank.
Another heat exchanger is placed between the insulated underground heat storage unit and the cold water supply.
8 sun-tracking solar collectors’ hydraulic and electrical connections are completed, and the solar collectors are now fully functional.
Installation Of Parabolic Trough SCs
The hydraulic connections of the sun-tracking sCs
ZBK Demo Site - Sun-Tracking PV/T Systems
The RESHeat system includes two PV/T systems for the ZBK demo site. The foundation of PV/T systems was done on both sides of the insulated underground heat storage unit.
Each sun-tracking system consists of 12 PV modules with a total peak power output of 3.72 kW. The system’s electrical output is connected to an 8 kW inverter to be used firstly for the electricity consumption of the RESHeat system components.
Water/glycol mixture (35 %) is used as the working fluid for cooling PV modules in PV/T systems. Each PV/T system owns a pump for circulating the working fluid in the cooling system.
The immersed heat exchanger inside the insulated underground heat storage tank is connected to PV/T systems. Therefore, the thermal energy generated within the PV/T systems is rejected to the water inside the underground heat storage unit.
The heat generated within the system supports the lower source of the heat pump to allow the operation of the heat pump with high COP.
The installed PV/T systems at the ZBK demo site
ZBK Demo Site - Heat Pump OILON RE 76
The heat pump is used to generate thermal energy to cover the heating demand of the space heating and the domestic hot water when there is not enough thermal energy generation within the sun-tracking solar collectors.
A water-to-water heat pump RE 76 with a maximum heating capacity of 95 kW is installed at this demo site.
The heat pump consists of 2 evaporators and 2 condensers.
The ground heat exchangers are connected to the down-source side of the heat pump. The return of the source side of the heat pump is either circulated through the heat exchanger or circulated through the ground heat exchangers. The load side of the heat pump is connected to the central heating buffer tank for space heating and the hot side of the 95 kW heat exchanger.
The RE 76 heat pump in boiler room
ZBK Demo Site - Underground heat storage unit
An insulated underground heat storage unit, with a 50 m3 capacity and immersed heat exchanger, is used to store thermal energy for the source side of the heat pump.
The excavation area is surrounded by barricades in order to eliminate any risks, and only authorized persons are allowed to enter the area.
A crane is used to place the underground heat storage unit. The insulated underground heat storage unit is filled with water. The immersed heat exchanger is connected to the outlet of the PV/T system, and the water/glycol mixture is circulated.
The water inside the insulated underground heat storage unit is connected to three heat exchangers. The water is circulated through the hot side of one of the heat exchanger for delivering thermal energy to the lower source of the heat pump.
Another connection of the insulated underground heat storage unit is to the cold side of the other heat exchanger. The last connection of the tank is made to the hot side of the heat exchanger in order to reject heat to the cold domestic hot water supply.
The underground storage unit placement area
Placement of the insulated underground heat storage unit at the ZBK demo site
ZBK Demo Site - Vertical Ground Heat Exchangers
15 each 100 m deep vertical ground heat exchangers are installed at the ZBK demo site for dissipating the excess heat to the ground during non-heating seasons to utilize the thermal energy for the lower source heat pump during the heating seasons.
Once the boreholes are prepared, U-tube heat exchangers are placed. The hydraulic connections of the ground heat exchangers are completed at the demo site.
Piping of ground heat exchangers
The RESHeat system started to provide heating for the ZBK demo site building as the protocols were confirmed.
The SCADA system installed at the demo site is shown below.
The SCADA System at the ZBK demo site
TOP-CEZAR Demo Site, Limanowa, Poland
The RESHeat system is being developed at Top-Cezar V, Limanowa demo site and is planned to cover the energy demand of the single storey of a multi-family building, which consists of 9 appartments.
The appartments occupy 433 m2 of the building. The heating system of the building is powered by two gas boilers, Dietrich 75 kW each.
The heating demand of a single storey of the building is 29.10 MWh/year.
test
TOP-CEZAR building in Limanowa/Poland
test
TOP-CEZAR Demo Site - main components of the rESHeat system
- 46 stationary PV panels with a power output of 20.24 kW peak;
- 5 sun-tracking parabolic trough collectors with the thermal output of 19 kW peak;
- 2 sun-tracking photovoltaic/thermal (PV/T) systems, each consisting of 12 PV modules and 1 cooling system at their rear side;
RE 33 heat pump with a maximum heating capacity of 42 kW;
5 U-tube vertical ground heat exchangers, each 100 m deep;
1 insulated underground heat storage tank with a capacity of 50 m3 and immersed heat exchanger.
The concept installation of the RESHeat system for the TOP-CEZAR demo site
TOP-CEZAR Demo Site - Stationary PV Modules
In the TOP-CEZAR, 46 PV modules, each with a power output of 440 W, are installed during the project documentation. The peak power output of the stationary PV system is 20.24 kW .
Firstly, the rack for the installation of the PV modules is prepared. While preparation of the rack, PV modules are installed simultaneously. The generated electricity in the form of a direct current (DC) will be converted to an alternative current (AC) before connecting to the grid and the RESHeat system components.
A 20 kW inverter was chosen to connect the output of the PV system. The generated electricity is consumed by the RESHeat system components, and the excess electricity is sold to the grid.
Completed stationary PV system installation At The TOP-CEZAR Demo Site
TOP-CEZAR Demo Site - Sun-Tracking sun collectors
The sun-tracking parabolic trough collectors are used to generate thermal energy to cover the domestic hot water demand mainly of the inhabitants in the TOP-CEZAR demo site building.
5 sun-tracking solar collectors are used to generate thermal energy with a peak of 19 kW. A water/glycol (35%) mixture is used as the working fluid. The output of the solar collectors is connected to a three-way valve.
The sun-tracking solar collectors’ hydraulic and electric connections are completed, and the solar collectors are now fully functional.
Installation of parabolic trough solar collectors At The TOP-CEZAR Demo Site
The hydraulic connections of the solar collectors At The TOP-CEZAR Demo Site
TOP-CEZAR Demo Site - Sun-Tracking PV/T systems
The RESHeat system includes 2 PV/T systems for the Limanowa demo site. The construction of the sun-tracking PV/T system starts with the arrangement of the foundation.
The sun-tracking PV/T systems consist of 12 PV modules and a cooling system at their rear side for harvesting the waste heat from modules. Each sun-tracking PV/T unit produces 5.18 MWh/y of thermal energy and 2.8 MWh/y of electricity energy annually.
Water/glycol mixture (35%) is used as the working fluid for cooling PV modules in PV/T systems. Each PV/T system owns a pump for circulating the working fluid in the cooling system. The output of each PV/T system is connected to the hot side of a heat exchanger. The cold side of the heat exchanger is connected to the manhole collector well.
The harvested heat is utilized for the lower source of the heat pump to maintain the coefficient of performance (COP) of the heat pump as high as possible.
The PV/T installation At The TOP-CEZAR Demo Site
The manhole collector well at the tOP-CEZAR demo site
TOP-CEZAR Demo Site - heat pump OILON RE 33
The heat pump is used to generate thermal energy to cover the heating demand of the space heating and the domestic hot water when there is not enough thermal energy generation within the sun-tracking solar collectors.
A water-to-water heat pump RE 33 with a maximum heating capacity of 42 kW is installed at this demo site.
The heat pump consists of 2 buffer tanks with 1 immersed heat exchangers.
The load side of the heat pump is connected to the central heating buffer tank, which is filled with water. The central heating buffer tank contains an immersed heat exchanger, which is connected to the domestic hot water tank.
The RE 33 heat pump in the boiler room At The TOP-CEZAR Demo Site
TOP-CEZAR Demo Site - underground heat storage unit
An underground heat storage unit, with a 50 m3 capacity and immersed heat exchanger, is used to store thermal energy and ground regeneration.
The excavation area is surrounded by barricades to eliminate any risks, and only authorized persons are allowed to enter the area.
The underground heat storage unit is filled with water, and the water/glycol mixture is circulated through the immersed heat exchanger. The immersed heat exchanger is connected to the lower source of the heat pump to maintain high COP during the heating season.
A submersible pump is placed inside the underground heat storage unit to direct the water to the cold of the heat exchanger when there is excess heat from the sun-tracking solar collectors.
The underground storage unit placement area At The TOP-CEZAR Demo Site
TOP-CEZAR Demo Site - vertical ground heat exchangers
5 U-tube vertical ground heat exchangers, each 100 m deep, are installed at the TOP-CEZAR demo site for dissipating the excess heat to the ground during non-heating seasons to utilize the thermal energy for the lower source heat pump during the heating seasons.
The ground heat exchangers are also connected to the collector well. Water-glycol mixture (35%) is used as the working fluid in ground heat exchangers.
The vertical ground heat exchangers also help to restore the ground’s capability to deliver heat after the heating season.
Top-Cezar V demo site SCADA system
ATER Demo Site, Palombara Sabina, Italy
The demo site in Italy is a residential building owned by ATER Provincia di Roma (Territorial Housing Agency) built in 1980-85, sited in Palombara Sabina, Viale Adriano Petrocchi 13.
The ATER building is a multi-family building with 13 appartments. A natural gas boiler system serves as the central heating system. The maximum heat input is 69 kW, while the maximum and minimum helpful heat output are 65 kW and 51.8 kW, with an efficiency of 0.96.
The heating demand of the building is 54.92 MWh/year, and the cooling demand of the building is 37.70 MWh/year.
ATER demo site building, Palombara Sabina, Italy
ATER Demo Site - main components of the RESHeat system
- 75 stationary PV/T modules with an electrical power output of 22.5 kW peak;
- RE 56 heat pump with a maximum heating capacity of 85 kW and maximum cooling capacity of 74 kW;
- 4 buffer tanks with capacities of 1,000 L without immersed heat exchangers, 2 buffer tanks with capacities of 800 L with 2 immersed heat exchangers;
- 1 dry cooler with a maximum capacity of 146.7 kW;
- 26 fan coil units for heating and cooling the apartments.
The design concept of the RESHeat system for the ATER demo site
ATER Demo Site - Stationary PV/T modules
In the ATER Building demo site, 75 stationary PV/T modules, each consisting of 300 W PV modules and a cooling system at their rear side for harvesting the waste heat from modules.
The roof of the building is prepared for the workers, and safety measures are taken. The rack system is constructed for PV/T modules.
Once the rack system is prepared. The PV modules, along with the cooling system, are placed on the roof of the demo building. The piping system of the cooling system is completed.
Another rack system is prepared for the piping and the collector system. The working fluid circulates through the cooling system on the rear side of the PV modules to harvest the waste heat and cool down the PV modules to maintain the maximum power output.
The rack system for PV/T modules At The ATER Demo Site
The PV/T system installation At The ATER Demo Site
ATER Demo Site - dry cooler
1 dry cooler with a maximum capacity of 146.7 kW is used to gain thermal energy from the air to the working fluid (water/glycol mixture) during the heating seasons for the down source of the heat pump.
During non-heating seasons, the excess heat is rejected to air from the working fluid using the dry cooler.
A crane is arranged to place the dry cooler on the spot next to the building.
test
Dry cooler placement at the ATER demo site
ATER Demo Site - fan coils units
In the ATER demo site, 26 fan coils are used to provide heating during the winter and cool down the space during the summer periods. The power of each fan coil was sized according to the heating and cooling demands of the apartments.
Firstly, the installation of the piping for the fan coils is realized at the demo site. Once the piping work on the outside envelope of the building is completed, the piping of fan coils is connected to the boiler room.
The working fluid is injected into the pipe system, and it is pressurized to analyze if any pressure drop occurs.
Fan coil (left) and boiler room (right) in one of the ATER demo site apartments
ATER Demo Site - heat pump OILON RE 56
The heat pump RE56 was chosen for the demo site to provide heating and cooling to the apartments. The heat pump is delivered to the demo site and placed in the boiler room.
The hydraulic connections of the buffer tanks, implementation of the circulation pumps, valves, measurement devices, integration of heat exchangers, and piping of the system are ongoing.
In addition to works carried out on the hydraulic side of the RESHeat system, the control box, along with the protection and control components, are placed at the demo site.
