Energy Efficiency in Restaurants – Part 2

Part Two of a Series

By Martin Flusberg

Control HVAC Costs

In the second of the series of posts on energy efficiency in restaurants, let’s look at the highest cost in most areas of the country – heating and cooling.

The starting point is to make sure that HVAC settings consider comfort first, but also costs.  Adjusting settings by as little as 1 or 2 degrees can actually have a significant impact on costs, and may have minimal impact on comfort.  (If you spend $1,000 per month on air conditioning, for example, raising the temperature setting can save you between $160 and $400 over the course of a summer; more in very hot climates).  Installing programmable thermostats – particular those that connect to the Internet and can be controlled remotely – can help ensure that policies on thermostat settings can be maintained.

Many restaurants have installed Economizers that reduce the need to run an HVAC compressor by pulling in outside air at certain temperatures.  But, dampers on Economizers often need adjustment within a few short years.  Dampers stuck in the open position is a very common occurrence – and this can increase HVAC costs by as much as 50% by letting hot air in during the cooling season and cold air in during the heating season.  Conversely, problems with these systems may result in compressors running even in temperature ranges when they should not be.  Making sure systems are routinely checked and maintained can help reduce or eliminate these problems.

There are also a range of approaches to automatic monitoring of HVAC systems that can help avoid problems and keep costs down; these approaches cover the gamut from inexpensive to very expensive to implement.

For example, on the inexpensive side, it is possible to simply monitor the temperature of the return air going to the A/C system, and the air coming out of the nearest register.  A temperature difference outside the range of 14◦ F to 22◦ F may suggest a problem, and therefore should result in the system being checked.

There are also systems in a variety of price ranges for performing a broader range of HVAC fault detection.  These measure temperature readings, pressure levels, and humidity levels, and compare the results with expected levels to identify possible faults related to refrigerant charge, compressor valve leaks, condenser and evaporator fouling, and a range of other factors.   (The National Institute of Standards and Technology has published a methodology for performing HVAC fault analysis).  When properly implemented, these systems can actually reduce the need for preventive maintenance, reduce repair costs, and increase the life of the equipment.