In a commercial HVAC system:
1. Head Pressure: Add a water regulating valve to each individual Heat Pump. By doing this addition we can increase and maintain the head pressure @ 110 degrees F and run the unit to its maximum efficiency. This has the potential to decrease energy consumption from the unit by 10%-20%. In addition to maintaining our head pressure, we also reduced the amount of water supplied to all units. This will increase the life and efficiency of your water loop water pumps.
2. Water loop Temperature: Your water loop temperature should be between 60 - 90 degrees F. The optimum water temperature is 80 degrees F. Maintaining your water loop temperature at 80 degrees will keep your heat pumps in their optimum working conditions. This will also help with nuisance issues (such as heat pumps tripping out on high head).
3. Filter Changes: Your filters need to be replaced as often as 2-3 months. My professional suggestion is to use MERV 8 standard cap filters, these provide the most protection from dirt and dust without putting a load on the indoor fan motor. Efficiency may drop by up to 20% due to dirty filters or clogged evaporator coils.
4. Digital Thermostats: New digital thermostats can provide 1% energy savings for every degree of temperature change for an 8 hour period. Ex. (thermostat dropped 3 degrees over 8 hours, this equates to 3% energy savings). These savings are easily attained as we program all thermostats to have a night set back (Generally these set backs last 8-12 hours). New thermostats have more aggressive algorithms programmed into them, this gives us a more precise temperature control and more savings. New thermostats also have an intelligent recovery system, this allows the thermostat to learn your HVAC equipment and the time it takes to cool/heat the surrounding area (More savings). The thermostats that we use, also come with a digital lock code (4 numerical inputs), this allows us to get rid of those ugly thermostat lock boxes.
Estimated Cost for Changes:
Head Pressure Regulating Valve (Installed and adjusted) $ 600/unit*
Digital Thermostat (Installed and Programmed) $ 550/unit*
*The above prices are a rough estimate
Coupling all of these methods together in a commercial building, we can expect to see an annual savings of $100-175 per unit per year.
For example, a building with 200 water sourced heat pump units, could potentially save $20,000 - $35,000 per year.