Commercial HVAC Systems

We generally start our evaluations of existing buildings with a building
energy audit, and come up with a list of suggestions for ways to improve
building energy efficiency. But you may just want to focus on the HVAC
system or systems.

Expenses for heating, ventilation, and air conditioning (HVAC) in commercial
and industrial buildings represent significant portions of the total electric bill, and
so provisions for conditioning the working spaces and surroundings are likely to feature
prominently in our recommendations from a complete audit. If your equipment is older, has
not been well-maintained, or you suspect is operating at less than optimal efficiency, you may
want to start with an evaluation of the HVAC system, especially if you have multiple units.

In that case, we start with a screening audit, a basic assessment of the existing equipment, its age, its
apparent condition, and a few other items. It identifies potential cost-effective energy efficiency measures. This is the basis for formulation of a preliminary energy assessment (PEA), in which we gather more detailed information in order to quantify the specific potential energy savings and other financial benefits. It includes a detailed cost-benefit analysis to compare the possible replacement systems or retrofitting work with the existing systems.

You may want to consider replacement of major parts of the system--chillers, cooling towers, even fans and air handlers. Cost savings may not be the only reason--newer refrigerants are less harmful to the environment, but older systems usually cannot be retrofitted to use them without major expense, if at all. If you know that you need to replace equipment, either on your own or as a result of our studies, it would be wise to invest in commissioning the equipment. That involves specifying it properly for its intended use, making sure it is delivered and installed as specified, and testing it over a range of conditions to make sure it is working according to specifications.

Of course, capital expenditures are usually involved to change and/or add components, and they can be quite substantial. But rebates are often available that offset a significant portion of the costs, and we will help you qualify for and obtain them. Depending on the size of the system and other factors, a feasibility study may be warranted to define alternatives, costs and savings more precisely than the PEA, including the logistics of implementation, and to provide justification for the investment on a cash-flow basis to all decision-makers involved.

Older systems are likely to be relatively energy-inefficient. Frequently, they can be tuned up to operate better for relatively little cost; we can perform a comprehensive servicing. This is useful if the equipment has not been properly maintained--like most equipment. Significant improvements in operating efficiency may be possible. Or, we can perform a retro-commissioning to evaluate the entire system and compare its current performance with specifications.

Advances in control technology have made it possible to retrofit HVAC systems that operate on compressed-air controls, to integrate every thermostat into the building control systems. This brings complex systems that are otherwise functioning well into the 21st century.