HeatVentors server cooling using CrodaTherm™
HeatVentors design and install advanced thermal energy storage (TES) systems using our CrodaTherm™ bio-based phase change materials (PCMs).
In this case study, we review a TES HeatTank system, which was installed to improve the efficiency of an existing telecommunications server room.
After one year, operational costs were reduced by 51% and is forecast to return on the initial investment after 4 years.
Rita Andrássyné Farkas, CEO of HeatVentors said,
“Trust is very important in the energy efficiency sector. We are looking for long-term cooperation with our customers, so it is crucial to calculate the real ROI for them.
For this, we have to sell high and constant quality products, which means that we have to use high and constant quality PCMs in our storage.
We investigated and tested many different PCM from many different suppliers and we chose CrodaTherm, because the properties of their materials are totally the same as indicated on the Data Sheet and they provide - high and constant quality.”
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The need: improve HVAC efficiency
HeatVentors received a client request to reduce the operating cost associated with cooling the telecommunications base station installation.
The client had servers in the telecommunications base station that produced between 2.5 and 3.5 kW of heat. Two 6 kW air conditioning systems were used to achieve a server room temperature of 26 °C (78.8 °F).
Due to the large expenditure on electricity for cooling equipment, with the risk of equipment failure if temperatures were not properly managed, there was an opportunity to significantly reduce operational costs and improve overall energy efficiency.
The solution: a HeatTank TES system
HeatVentors proposed the installation of a HeatTank TES structure, using CrodaTherm PCMs, in a room separate from the servers. It included two heat exchange surfaces, refrigerant pumps, and expansion tanks.
This design allowed the cooling potential of the mountainous air outside of the building to be stored and utilised for server cooling.
Even in hot summer weather, the design allowed excess cooling potential to be stored from the air conditioning system, so that peak thermal demand could be met during temperature peaks on a hot summer day.
Figure 1: HeatTank design proposed by HeatVentors for their client for cooling their servers in a telecommunications base station
The result: improved efficiency and reduced operational costs
The HeatTank system was compared to the existing air conditioning (AC) only HVAC system, comparing 3-day periods with similar weather conditions.
Full results: efficiency under different operating conditions
Operation without HeatTank
The cooling needs of the server room were well below the cooling capacity of the installed HVAC system. As such, the air conditioning units turned on and off about 10-12 times per hour as they were not needed constantly. However, when idle the AC systems continued to consume energy to circulate air.
During hot summer months, especially during the day, AC demand was higher, and more energy was used.
Operation with HeatTank using free cooling throughout the day
Cooling demand was primarily met by free cooling when temperatures outside were below 26°C. This meant the cooling potential of the outside air met the server cooling needs with minimal energy investment from the newly installed HeatTank system.
In this instance, the air conditioner operated with almost the same performance, but with almost 6 times the energy consumption, whereas the HeatTank storage solution, operational from the 30th May, was able to take advantage outside temperatures for cooling, resulting in lower energy consumption, even in summer months.
This represented an 82.4% energy saving.
| Date | Temperature/ °C | Electricity consumption /KWH | ||
| Average | Max | Min | ||
| 17th May | 10.9 | 16.7 | 7.3 | 28.9 |
| 30th May | 10.0 | 15.1 | 4.4 | 5.1 |
Operation with HeatTank using free cooling overnight
When outside temperatures increased during the day, it eliminated the possibility of free cooling over the 24-hour period. However, with the HeatTank system, cold energy could be stored overnight. During the day, the cold energy store was used to cool the server room with minimal energy input.
This represented an 85.7% energy saving.
| Date | Temperature/ °C | Electricity consumption / KWH | ||
| Average | Max | Min | ||
| 2nd April | 17.7 | 21.4 | 13.3 | 38.0 |
| 5th April | 17.4 | 23.5 | 11.4 | 5.4 |
Operation with HeatTank without free cooling
This represented a 20.1% energy saving.
| Date | Temperature/ °C | Electricity consumption / KWH | ||
| Average | Max | Min | ||
| 4th July | 22.8 | 30.0 | 47.9 | |
| 7th June | 22.8 | 30.5 | 38.3 | |
Result after 1 year of operation
The total electricity saving after one year was 51.3%, with an estimated ROI time of 4 years.