PCM Applications - Passive Cooling
Passive Occupied Space Cooling
The night-time cooler ambient can be used to charge the latent heat capacity of various “ Positive Temperature Eutectic” solutions between +4 °C (39F) nd+27 °C (80F) without the use of any refrigeration machinery by simply allowing the surrounding air to freeze these solutions. It is then possible later for the stored energy by the Positive Eutectic Thermal Energy Storage “PETES”, to be released back to the occupied space during daytime to handle the heat gains. This technique is generally called Passive Cooling and it may enable the charging process to take place by means of free cooling, i.e. without running the chillers and as a result becomes a very economical and environmentally friendly system. Furthermore, PETES opens new opportunities to explore heat balance for the existing and new systems, which could offer significant overall system efficiency improvements.
Many high rise building tends to turn off the air conditioning but many of these buildings might have banks / offices whereby having small / medium IT rooms with lots of computers which would be still running over weekend / night time and without cooling they over-heat. In order to over-come this over-heating individual clients can use an IT back-up PCM cooling module which is charged during normal office hours utilising the central cooling system and provides 48 hours cooling over weekend without the need for central air conditioning system.
South facing architecture study areas and some of the offices were over heating and by simply adding 27C ( 80F) TubeICE at high level within the occupied areas almost all of the sensible heat loads are handled by the passive cooing. As these PCM tubes are static, no moving parts and any power requirements as the cooler night ambient is enough to freeze them naturally, it offered a maintenance and energy free cost efective solution for the over heating issue.
OMAN ACROSS AGES MUSEUM, MUSCAT, OMAN (468 KB) Considering 55C (130F)peak day time ambient temperature vs. 28C (82F)night time ambientcondition if one can store that cool night energy and utilising this FREE stored energy duringday peak period one can reduce the outside air cooling demand during peak ambient conditions significantly. For this purpose a special tunnel built to accommodate the PCM containers whereby when the surrounding air temperature is less than the PCM solution generally during night time, these containers freeze naturally by the surrounding cooler night ambient and later this stored energy in the form of latent heat can be released back to the air supply system during daytime to cool the incoming air for the outside air supply requirement for the museum. Almost the total daily sensible heat gains due to outside air supply can be absorbed by the passive cooling tunnel.As the outside air intake is crucial for public spaces like museums by simply storing cool night energy the overall cooling demand can be reduced significantly especially locations whereby the day time ambient reaches as high as 55C (130F) anywhere in the Middle East.Each chamber 2.5m(8’) (W) x 2.0m (61/2’) (L) x 2.5m (8’) (H) filled with 10 wide x 58 high FlatICE stack.Total 4 chambers accommodate 9,280 FlatICE filled with S32 (+32C/ F) PCM solution providing 2.0 MWh (595 RT-h)TES capacity.
As part of the environmental awareness of the cooling University of Cavindish London campus implemented a passive cooling 27C9 70F) PCM modulss to compliment their VRV system whereby the lead is taken by the energy free passive cooling and any top up latet cooling loads handled using conventional VRV system.
Existing Bond Street shop was in an old Listed building whereby with very little external walls / areas to sufficinet A/C outdoor units so by simple adding the 22C ( 70F) PCM TubeICE banks like a Fan Coil Unit (FCU) set up for the existing A/C system nd rnning the A/ over night using lower ambinet and electricity cost this PCM addio is enabled the designers to shift half of the day loads for the peak summer seasons but also almost 9~10 months of the year using cooler ambinet air to charge these TUbeICE banks without any mechanical cooling i.e. free cooling and this way designers not only solved the physical restriction issue but provided a maintenance free and cost effective technical solution for the building.
As part of the energy drive and environmetaly friendly option designers applied the TubeICE passive cooling concept to all staff offices whereby the night cooler air charge i.e. freeze the 27C (81F) PCM material and in return during day time heat generated within the room as well as solar gains absorbed by the PCM to keep the office area below the upper high temperaure limits and provided an energy free comfort cooling option not to mention a maintenance free benefits.
Top floor an existing building is converted to have a dynamic passive cooling using FlatICE containers forming an Air Handling Unit (AHU) format with circulation fans and using cooler air air circulation freeze +22C (71F) PCM and once they are frozen during office hours this stored energy is used to handle the sensible loads of the space as a free energy.
One of the main problem of the latest high specification UK schools can be described as the overheating during a few days of the year especially if the building facing south but as this only occurs a few days of the year any conventional A/C would be far to exensive to install, run and most imporatntaly maintain so a simple maintenance free PCM based passive cooling offers a cost effective and environmentally friendly option to over come this over heatng issues.
Again like the application above more and more schools are facing over heating occosionally and a simple PCM based passive cooling offers a simple, maintenance free, practical solutiion whch can be installed quickly to any new or retrofit applications. A simplem cost effective and maintenance free PCM based passive cooling can be applied to any existing or new CLASSROOM or LECTURE THEATRES as illustrated in these examples.
Passive Unoccupied Space Cooling
It is imperative to keep electronics under 45 °C (+113 °F) in order to keepsystems functioning. PCM systems freeze over night, even in desert climates, soak heat from the electric circuits, melt and release cool during the daytime.
Performing the role of a thermal shock absorber, the PCM prevents electronics exceeding their critical temperature.
PCM packs avoid ambient as well as battery charging and discharging periods overheating issues by simply storing energy during off/cool periods.
PCM technology gives extended life to the batteries by keeping the temperature down. Cooler batteries result in longer life and better performance.
Shelter Passive Cooling
The PCM freezes overnight to absorb heat during hotter daylight hours as well as internal heat generation in applications such as remote pump-station control rooms, to provide an electric-free solution.
Electronic Back-up Cooling
Many I.T. centres have their power supply backed up by generators or UPS for the computers. Unfortunately, as soon as the power goes off, the temperature rises. The PCM acts like a thermal sponge, soaking the heat from area and offers an electricfree back-up cooling solution.
Passive Cooling Catalogue (1,489Kb)
Passive PCM Cooling Products and Application Examples.
Passive Cooling Applications (300Kb)
Shelter and electronic passive cooling PCM applications around the World.
EcoPac Box (130Kb)
Shelter / Electronic Housing Passive Cooling Back-up unit.
EcoPac Box Trial Unit (312Kb)
Design and test data for a Shelter / Electronic Housing Passive Cooling Back-up unit.
EcoPac Tile Catalogue (440Kb)
Passive PCM cooling tiles for passive cooling applications
Shelter TubeICE Passive Cooling (90Kb)
Global electronic shelter cooling application examples utilising TubeICE product.
Shelter Design (130Kb)
A typical shelter passive PCM cooling concept.