Feature
Terry February
An ice thermal storage vessel and inventory meter .
solution highly appealing as well as competitive in our drive to reduce costs and energy demand .
SYSTEM AND SIZING CONSIDERATIONS Ice storage , as mentioned , can be included through a number of techniques and systems that are available in South Africa , and in
part or in full support of an existing system . It can be retrofitted to an existing system too .
“ As the largest contractor installing ice thermal storage in South Africa , we have done some very big projects , for example , tanks with a diameter of 3.5 meter and length of 13 meters and also the small installations . We have , over the past 12 years , had the opportunity to see what systems perform the best . The designs come in all shapes and sizes and as already mentioned , this solution is flexible . An important factor to note with this solution is that at night ambient conditions are generally much cooler and so the process of building your ice , besides costing even less as you are using that energy out of peak times , it ’ s a lot more efficient than trying to build ice at a 35 ° C daytime temperature ,” says Jan Wibbelink , managing director of HVAC Installations .
Placement of the thermal storage tanks that vary in size from a few cubes to massive tank structures the size of a sports field , can be below ground , in basements or plant rooms ; on the roof depending on size and weight considerations , or even within a building ’ s structure where spaces are available . These can include shafts above or below lifts , stairwells , as well as service duct areas .
The ‘ tanks ’ required for building ice can be made out of a variety of materials , including plastic , steel and concrete . The main challenge to contend with is the fact that the storage tanks are heavy . One ton per cubic metre , so the bigger the tanks the more consideration needs to be given to weight parameters . This too could limit installation within or on top of a structure . Larger installations mean weight into hundreds of tons .
Positioning is also important to consider because of the chilled water piping that is required to be installed . Some clients may also not want tanks on the roof because of aesthetics or the space is used for other purposes , like entertainment , while other clients may not want storage in the basements because they may rent out the parking space .
When sizing the system , the two main considerations are addressing the building ’ s heat load , and secondly how long it
16
RACA Journal I April 2021 www . hvacronline . co . za