Thermal Energy Storage (TES) may be considered as a useful tool to reduce the cooling load requirement by method of spreading day time loads over 24 hour period utilising the naturally occurring ambient temperature difference.
The night-time cooler ambient can be used to charge the latent heat capacity of various Positive Temperature Eutectic also called Phase Change Material (PCM) solutions between +4°C ( 39°F) and +117 °C (243°F) without using any refrigeration machinery by simply allowing the surrounding air to freeze these solutions. Later the stored energy by the Positive Eutectic, PCM Thermal Energy Storage can be released back to the occupied space during day-time to manager the heat gains.
This technique is generally called Passive Cooling and it may permit the charging course of action to take place by method of free cooling, i.e. without running the chillers and as a consequence becomes a very economical and environmentally friendly system. Furthermore, PCM energy storage opens new opportunities to analyze heat balance for the existing and new systems, which could offer meaningful overall system efficiency improvements.
Alternatively, the sun energy during day-time is stored and later utilised during colder night-time to heat the space for a free heating in addition as storing heat in the hot water circuits.
Privatisation has produced a new kind of energy market whereby the period of energy usage and the kind of energy used is becoming the main criteria for price structuring instead of overall energy consumption. Hence, cooling systems must intended to provide sufficient flexibility for load shifting and a PCM Thermal Energy Storage technique can be considered as a useful tool to unprotected to this aim.
Building sets must intended to provide sufficient flexibility for load shifting and energy usage control in order to unprotected to the most economical operation. A PCM Thermal Energy Storage technique whereby “Storing High or Low Temperature energy for later use in order to bridge the time gap between energy availability and energy use” can be considered as a useful tool to unprotected to this aim.
Passive Cooling PCM Thermal Energy Storage (TES) benefits can also be applied for electronic chamber, shelter, telecom shelters, far away pump and electric control cabinet cooling for far away location whereby the without of electricity deleted the mechanical air conditioning or alternatively mechanical cooling free applications around the World.
These Passive Shelter Cooling systems can already function in hot countries like the Middle East due to higher space temperature (45ºC / 113°F) requirements in comparison with Office Cooling. A PCM solution of 32ºC (89.6°F) is sufficient to continue the room temperature below 45°C (113°F) by simply using the temperature swing between day and night time.
The same concept has also been successfully applied for cold storage transport applications using Eutectic beams. The majority of the perishable food must be chilled during transport but the cost of refrigerated truck restricts the use of transport cooling in particular in the third world where the biggest waste occurs. A PCM, Eutectic filled high ceiling beams can be simply charged using standard cold storage can keep the product temperature under control at a very attractive lower cost to install and run.
These passive cooling units can be supplemented using a very small refrigeration compressor or a chilled water circuit for lower temperatures but products like chocolate, bakery products and flowers can be easily maintained under control by simply charging these beams / containers over-night and utilising the stored energy during day-time transport. Furthermore, this concept enables the owners utilise their standard Lorries to be used as refrigerated trucks during harvest / peak season at a fraction of the cost for a traditional refrigerated truck.
HVAC / Air Conditioning PCM passive cooling concept offers mechanical refrigeration free passive-cooling by simply storing the night cool energy and releasing the stored cold latent heat capacity during day-time to keep the space temperatures under control. Low ambient temperatures coupled with free cooling offer a meaningful reduction of energy consumption relating to the cooling operation, which is in the vicinity of 16-46 % depending on the kind of passive cooling unit and location.
Based on the applied projects, ambient profiles in many parts of the world and associated feasibility studies indicates that PCM assisted Passive Cooling concept offers economical and very environmentally friendly cooling options. In any country whereby the night ambient does not allow being sufficiently low enough to charge PCM Thermal Energy Storage (TES) cells over-night, a supplementary dry cooler and / or small chiller can be additional to top up the difference between the ambient and PCM temperature for an economical solution.
Modern society’s reliance on refrigeration and air conditioning indicates that refrigeration and the associated environmental issues will be with us for a important time and consequently one has to utilise existing and obtainable different technologies with minimum usage of energy.
A Positive Temperature Eutectic ” PETES ” Thermal Energy Storage not only provides the end user with an Environmentally Friendly design but also the following additional benefits can be obtained:
o Reduced and No Refrigeration Equipment
o Capital Cost Saving
o Reduced Maintenance.
o Energy Cost Saving
o Reduced CO2 Emission
o Environmentally Friendly Installation
o Improved System Operation / Reliability
o Flexibility for the Future Capacities Changes
The temperature ranges offered by the hypothesizedv Phase Change Materials solutions utilise free ambient cooling, traditional chilled water temperature ranges for both the charging and discharging sides of the system. Hence, they can be applied to any new or retrofit application with minimal technical and economical impacts.
Finally, the possibility of Free Cooling Cycle TES system offer new horizons for designers to control the energy balance to match the load and electricity need / consumption of the system as a whole.