PROJECT 31 downtime by strategically timing operations to coincide with off-peak electricity hours ,” says Marais , “ To achieve this , we proposed a strategy of closely monitoring campus energy demand and implementing loadshifting techniques .”
The strategy included 25 % -oversized storage vessels so that there would be increased water reserves allowing operations to continue during peak demand periods . This meant that the system could automatically be switched off when maximum power consumption is reached .
Mitsubishi heat pumps and Wilo pumps were used . “ Mitsubishi ’ s heat pump technology was selected for its efficiency and reliability ,” says Marais , “ There remains some reservation about heat pump technology in cold winter environments like the Free State , where many clients are adamant they want nothing less than 60 ° C water temperature .”
This temperature was set so that there was water safety , along with meeting heating needs and a desire to combat Legionnaires Disease .
Heat pumps were elevated off the ground to combat the challenge of icy ground conditions . Belimo energy valves were installed to provide real-time monitoring of unit performance , which is needed to verify the effectiveness of the system in varying weather conditions .
Twelve 45-kilowatt heat pumps were installed to serve four 19 000l tanks . Each tank has three internal heat exchanged coils and these are fed through a closed loop pumped water system from one CAHV 500 heat pump unit . To control the water temperature accurately , a Mitsubishi TW- TH16 temperature was installed .
These huge tanks had to be rigged and hoisted into a brand-new plant room . A dedicated facility was constructed for the heat pump cluster as well . PA
List of professionals
Name of company
Owner
Consulting engineer
Contractors
HVAC and associated product suppliers
Electrical Mechanical Wet Services Main Contractor HVAC & R MCC / DB Manufacturers Wet Services Electrical Controls / BMS Heat pumps HW tanks Pumps Energy valves Controls Controls
University of the Free State SHC Consulting Engineers SHC Consulting Engineers SHC Consulting Engineers DATEC Air Conditioning DATEC Air Conditioning Control Power Plumspec Botsepehi Electrical Atbro Systems Mitsubishi Electric Heat Transfer Engineering Wilo Pumps Belimo Johnson Controls Abtro Systems
June 2024 Volume 30 I Number 4 www . plumbingafrica . co . za