Page 36 - Climate Control Magazine September 2018

Time to reset your
energy savings strategy
THIS FEATURE PROVIDES TIPS ON HOW TO GENERATE IMMEDIATE ENERGY SAVINGS WITH MINIMAL INVESTMENT.
IT INCLUDES A temperature reset strat- egy for chilled water and condenser water delivery as well as tips on how to retrofit electronic expansion valves (EEVs) to re- place thermostatic expansion valves in vapour compression refrigeration systems that operate with direct expansion type evaporators.
These tips are provided by the NSW Office of Environment and Heritage (OEH) and the Aus- tralian Institute of Refrigeration, Aircondition- ing and Heating (AIRAH) and published in “I am your HVAC Optimisation Guide.”
Variable or floating temperature set point of heat- ing hot water (HHW), chilled water (CHW) and con- denser water (CW) is a control strategy whereby the temperature (or grade) of thermal energy is dynami- cally adjusted (or reset) to minimise the energy con- sumption of the associated HVAC equipment.
In practical terms, this means that HVAC con- trol algorithms attempt to provide:
• the coolest possible water for heating
• the warmest possible water for cooling
• the coolest possible CW for cooling of refrig-
eration equipment.
It should be noted that the optimisation strategies must take a holistic view of mini- mising total HVAC system energy consump- tion, as the singular optimisation of one piece of equipment in isolation may be to the detri- ment of another.
The algorithms must take into account sever- al different parameters, such as actual or field heat/cooling load, outdoor air (O/A) conditions, the efficiency, operational characteristics and limits of the installed HVAC equipment and the responsiveness of the HVAC control loop.
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