Air Conditioning Energy Saving

By July 9, 2021 No Comments
Air conditioning energy saving

You might not realize that air conditioning energy saving were possible or available today, without the high cost of upgrading to a new higher efficiency system. What could be done to any existing air conditioning system to reduce electricity usage?

That’s the same approach vootu took to identify precisely where energy was being wasted, and the largest component using energy is the compressor.

The system and compressor are activated by the thermostats calling for cooling, once that desired temperature is achieved the system shuts down. There’s really very little intelligence outside of the thermostat, which is basically a control switch.

First let me explain in basic terms how any Direct expansion air conditioning system works, this will serve to expose the opportunity to improve performance. There are basically two main parts to this system, the external component where the compressor and condenser coils are located and the internal component where the evaporator coils are located.  Both of these components are joined by refrigerant lines to complete the system. The compressor starts to pump the liquid refrigerant contained in the lines creating heat, at a certain pressure the expansion valve (TXV) will open and the hot liquid expands at a very fast rate creating a cold vapor that travels to the inside air handler containing the evaporator tubes. The internal warm air within the building is drawn into the return air ducts that feed the air handler, the warm air passes through the cold evaporator tubes and the heat energy is absorbed in to the tubes and the refrigerant. The now hot high pressure refrigerant vapor moves back to the outside condenser unit where it is cooled, assisted by the condenser fan drawing outside air over the coils to extract the heat. As the vapor cools it changes from a high pressure hot vapor back to a high pressure hot liquid, then it heads off back to the expansion valve once again. At all times the compressor pumps to maintain pressure within the system.

The obvious problem

The evaporator coils are necessary as a heat exchanger, however evaporators have a design temperature and once those coils achieve that temperature, you can continue to run the compressor but no further reduction in temperature will occur. Imagine for a moment the evaporator was a block of ice, melting as the hot air passes over it, once the room thermostat achieves its set temperature, the system turns off, so what happens to the block of ice created, it simply melts and all that energy uses to create it is  also wasted. That very same situation occurs in most air conditioning systems, some modern units do continue to run the evaporator fan longer to extract more of this cols energy, however their run time is based only on  time and not temperature so you still waste energy.

The solution

It appears that if the evaporator can only achieve a certain temperature, then once that temperature has been achieved we should question the logic of why the compressor continues to pump! One obvious reason being the desire to rapidly cool the building and remove any latent heat energy built up inside. Consider then that at some point in the day the overnight heat has been removed and the system cycles according to the thermostat calling for cooling but upon the evaporator coils reaching thermodynamic saturation point (coldest design temp) you turn off the compressor, keep the evaporator fan moving warm room air over the coils to be cooled all without the compressor needlessly running. Using temperature sensors on either side of the evaporator, the precise timing of running the compressor can be achieved allowing the run time to never exceed the design temperature of the evaporator coils.

The Product

Vootu designed and engineered a device to add the much needed intelligence to existing A/C systems. Being easily retrofitted, set up precisely to the age and condition of the system, with the ability to fine tune both return and supply air temperatures. The result is a control device we call I-Cool guaranteed air conditioning energy saving. Powered by the air handlers 24 volt electrical feed, this low voltage energy saving device has proved effective in over 3000 installations across the US and worldwide. I-Cool can also control further to enhance energy savings on three phase systems by integrating a variable frequency drive (VFD) programmed to slow down the air handler motor when the system enters energy saving mode. The additional benefits of this action are firstly the slower the air handler motor operates the less  energy it uses (affinity laws) The slower the warm air moves across the cold coils the more humidity is extracted from the air, increasing the feel good factor of less humid air. Lastly it has been measured and proven to extend the compressor run time off periods by Significant amounts, when the VFD is activated.

The results

I-Cool is a unique device produced by vootu and has been exhaustively tested and documented energy savings range from the lowest 20% savings on brand new systems to low 30% savings on older units. At no time did we record less than 20% improvements once the system was set up correctly. Countless reports of similar energy savings have been relayed back to vootu over the years. So if you want the benefits of air conditioning energy saving reach out to vootu, you’ll be surprised at low the technology costs and how fast your return on investment actually is.