PROJECT 35 efficient dual sets of variable speed drive ( VSD ) booster pumps catering for 24-hours back-up water storage for the specific building hot and coldwater demand .
Drainage was installed as uPVC and water supply was Copper Class ’ 0 ’, the hot water and hot water return piping is also thermally insulated to reduce heat loss and therefore saving on electricity / energy required for water heating .
Each building has its own dedicated hot water generation plant consisting of a ’ hybrid ’ system . Hot water is therefore generated by means of combining solar thermal with energy efficient air to water heat pumps and heat accumulator tanks , each system also has an electrical back-up element .
The entire hot water supply system has been designed as a re-circulating system ; hot water is supplied from the plant to the building by dropping in each duct to supply the residential apartment on the various floors . The hot water supply will convert to a ’ hot water return pipe ’ after the last draw off point on the lowest apartment level , it will then reticulate back to the main hot water return line through a thermo-static balancing valve before recirculating back to the hot water plant , which creates a ’ supply and return hot water loop ’ in the building .
One of the six borehole water storage tanks .
Each building consists of multiple ducts and ’ circulation loops ’ over multiple floor levels . Each individual loop is controlled by a thermostatic balancing valve with a pre-set temperature of minimum 45 ° C . When the specific loop temperature drops , the thermostatic balancing valve will open , causing circulation to the pre-set temperature and therefore ensuring that the circulating hot water loop remains at 45 ° C and above , always .
Each thermostatic balancing valve also has an integral temperature gauge to immediately ascertain the specific loop temperature on visual inspection . The above reduces the waiting time for hot water at showers , basins and sink in the apartments .
Challenges were to find the correct location for hot water plant on top of each building , this required close coordination with the architect as well as the structural engineer to ensure that the structure can take the load ( weight of the slab ) and that the overall look and design was aesthetically pleasing .
Typical water and waste configuration .
concrete had to be spot on , and time was not in their favour . It was critical that the plumber , inspection , and concrete casting ensured the respective work was done in order so no damage to pipework could occur . While time was not on the side of any of the three processes , it was managed with additional hours being spent working with each other . Most plumbing contractors can associate with this scenario .
Furthermore , and most importantly in ensuring that throughout this process the plant ( thermal collectors ) was facing the most efficient orientation and inclination .
Chatting with Aubrey Keble of KP Plumbing , the plumbing contractor , Blocks One , Two and Three were fed directly from municipal supply , all underground for both water and waste and suitably filtered as required . All soffit work was done in the basement , soffit being the highest point of the internal surface of a pipe at any cross section .
Checking of the gradient , alignment and bracketing is essential to ensure a professional installation . All piping from underground enters each level i . e ., ground , first and second floors via plumbing ducts on each floor , serving seven units per floor .
What was the biggest challenge ? All underground piping had to be cast into concrete so the timing between laying pipes and casting of the
All plumbing was according to SANS 10252:1 & 2 .
Also , in the basement are two 5000l storage tanks providing 10 000l of stored cold water and these are served by Grundfos booster pumps . The communal block is served by its own plant room .
KP Plumbing was responsible for the cold-water installation and installation of the brass and sanitaryware . All brassware and sanitaryware was procured by the client .
In keeping with SANS 10400 XA , which calls for 50 % alternative energy sources , Solar Heat Exchangers was appointed to install the solar thermal system . As was shown in a previous project , San Sereno , an Auria Group development , solar thermal offers substantial savings . In fact , such technology can no longer be seen as alternative but very much main line . PA
June 2023 Volume 29 I Number 4 www . plumbingafrica . co . za