As seasons change, building equipment functions also need to adapt. Ignoring changes to weather often causes building owners to suffer higher utility costs and causes occupant discomfort and complaints. If seasonal settings are addressed correctly, the Department of Energy says 5-15% savings in utility costs can be realized.
As the winter season ends and spring/summer seasons begin, it is important to inspect your building systems to help confirm you’re not going to be wasting energy or sacrificing comfort. As temperatures cool off from autumn going into winter, many changes may have taken place in multiple systems. Additionally, it is good to check for any systems that may have failed in the meantime.
For instance, condenser fans in air cooled HVAC systems tend to fail during first heat waves which hits in April or May. The lack of use during the wintertime and rain on the fan motors may cause motor failures. A quick test of your air conditioning systems to make sure that they go into full cooling before you really need them is a good idea.
Also, in HVAC systems, there may have been temperature set point changes or scheduling changes that were made during the winter (heating mode) that could affect your energy consumption when systems go into cooling mode. This happens quite a bit with heat pump systems when, during the wintertime, the schedule for turning on heat changes to be earlier in the morning. If that same schedule is still active when the system goes into cooling, it can make your air conditioning start much earlier than necessary which increases runtime and wear, as well as wasting energy. When checking your temperatures, also check the nighttime temperature setback which is sometimes referred to as an unoccupied temperature set point. These settings frequently get changed to accommodate winter as well.
Continuing with HVAC, it’s also a good idea to inspect those outside air/economizer dampers and your filters. Sometimes the air flow requirement for HVAC in cooling exceeds that of heating, and this can create an extra pressure drop at your filters and intake systems. Making sure they are clean and performing properly will reduce your energy consumption when more airflow is needed. In larger systems, air flow may be controlled from a central air handler that has static pressure set points. Ensuring that your system is always operating at the lowest possible static pressure set point while still providing comfort in the building can save a tremendous amount of energy.
Domestic hot water systems sometimes are changed to slightly higher temperature set points in the wintertime to quell complaints from tenants, and this elevated temperature may not be necessary in the summertime when domestic hot water demand is slightly lower.
For facilities that have noncondensing gas boilers for comfort heating, sometimes the wintertime can be problematic in creating condensate which can turn into burner failure. At the end of the heating season, you should inspect your comfort heating system for any damage or repairs that may be necessary. Summertime is the perfect time to work on your comfort heating system and therefore knowing what you’re going to need earlier in the year gives you a little bit more flexibility in budgeting.
Outdoor Lighting systems that are not fully automated may also need to have their times adjusted due to jumping into daylight savings. It’s a good idea to check your time clocks and photocells to make sure that they are still adjusted appropriately to prevent your lights from staying on too long and/or when daylight is available.
Hopefully for your indoor lighting, you have migrated to occupancy sensing controls and other automatic features. The lighting controls available today are highly reliable and much more affordable. When combined with LED indoor lighting, this results in significant cost savings in both energy and maintenance.
For facilities that have a mechanically ventilated parking garage, it’s a good idea to verify the calibration date of your carbon monoxide sensors. It is required by the California Building Code that these sensors get calibrated every year. If these sensors are not calibrated every year, the control systems are required to ramp your ventilation fans up to 100% full speed. This is at minimum a 200% increase in power being used by your fans system. This is because, in normal slow speed operation, the fans must use 30% or less of full power. Not having your sensors calibrated means that your fans are running at 100% power instead of 30% power.
The above steps should ensure that you don’t waste too much energy moving from season to season. If you or your maintenance staff would like any assistance in helping review the operations of your facility, or if you have any questions regarding systems that I didn’t include, then please reach out to us. For more information, contact Moe Fakih at VCA Green below.
Contributing Writer: Wayne Alldredge, Associate Director O&M, Energy, and Commissioning Services
Moe Fakih, Principal