Thermal energy storage with Phase Change Materials
Our patented technology
Thermal energy storage
We can store the cooling energy which was produced by low outside temperature and high efficiency. When the outside air temperature becomes high and the efficiency is low, we can use the pre-stored energy and turn off the cooling system. Also we can use the outside air to store the cooling energy like free-cooling but we use the cooling energy indirectly, so the disadvantages of free-cooling do not occur (dust and moisture).
For thermal energy storage traditionally we use water storages which stores energy by changing the temperature of the water, using the specific heat. However it is not efficient, because the specific heat of water is very low, only 4,2 kJ/kg K. An alternative solution is using phase change materials (PCM) and the latent heat for thermal energy storage. Instead of changing the temperature to store heat, we change the phase of the material (melting/solidification). This storage is more concentrated because the latent heat is much higher than the specific heat. (The latent heat of the water is 335 KJ/kg.) The melting temperature of water is 0°C which is too low for the servers and cooling to 0°C is expensive. The best solution is to use materials which melting point fits to the application.
The benefits of HeatTank
With our control system HeatTank always works at optimal level. Based on the inside and outside temperature, and the trends in the outside temperature, we can control the charging and discharging periods, to gain even higher energy savings.
After the personal audit we offer customised solutions. The biggest HeatTank is 500 kWh, but our storage is modular, we can use more HeatTank at once if needed, and the installed system is expandable if the needs are changing.
In addition we offer energy reports to our clients to be up-to-date regarding to the operation of their energy systems and the quantity of the saved electricity.
Thanks to our modelling algorithm we can offer fast solutions for the individual needs, and we can adapt HeatTank to every existing system.
How does it work?
Check our short demo video!
The Heatventors team worked with award-winning team of engineers and scientists to create next generation solutions that would meet the needs of different thermal energy users - suitable to a wide range of heat energy saving from individual users to industrial customers.
Check them out below!.
Data center/Telecommunication site cooling
Industrial heating/cooling/waste heat recovery
Offices buildings thermal energy management
Data Center COOLING
Check the details of our pilot project
Data centers/telecommunication sites needs to be cooled 24 hours at 7 days. They optimally operate at 24-28⁰C temperature. They are cooled similarly to industrial air conditioning using electrical energy. Unfortunately, the system is the least energy efficient when the temperature difference is the highest (i.e. the outside temperature is too high). However, in the night, when the temperature is low outside, the cooling system is much efficient, or even not needed. Storing the “cold of the night” and use it for cooling daytime could lead to significant savings.
Please check our CTOs Pich about this application!
Our pilot was installed to the data center of a telecommunication company. The heat generation of servers is 2,5 kW, the ACs (the air conditioners) are 2x6 kW and the optimal inner temperature is 26 °C.
The installed HeatTank has 25 kWh capacity, 100 kW performance, 0,5 m3 size, the used PCM changes its phase between 19-21 °C and it can cool alone for 8-10 hours.
At night the operation of the air conditioner (AC) is the most efficient (due to lower outside temperature). In this period PCM freezes due to heat removal. If the outside air is cold enough, air-condition is even not needed (this approach is called “free cooling”). When outside temperature rises PCM stays in solid phase (cooling capacity is set apart), and the AC is responsible only for cooling the room. When outside temperature is the highest, the AC operation is the least efficient. In this period PCM melts removing heat (while AC is turned off). When melting is finished the room is cooled by AC operation again.
At the end of the day the difference between the electrical energy consumption savings in Period III (green area) and the additional electrical energy consumption surplus in Period I and IV (red areas) results in a net balance: 20-40% energy saving. If the outside air is cold enough in the night, air-condition is even not needed, “free cooling” can be used to freeze the PCM and cool the servers, resulting in even lower energy consumption.
Overall we obtained 54% electricity saving on the cooling, which results in 4,06 years ROI.