Energy efficiency and audits: What does it mean to building owners?

History: Since the 1970 Arab oil embargo, the U.S. had been fluctuating between serious energy efficiency efforts and serious energy consumption practices. The government, starting with the timid EPAct 1992, with motor efficiency regulation, up to a strong EPAct 2005, with a mandate that all government buildings designed and constructed after a certain cut-off date, be designed/constructed with energy consumption rates of 30% below a standard base building that complies with ASHRAE Standard 90.1. The commercial HVAC industry spearheaded by ASHRAE on the other side had been very active in standardizing measures for energy efficiency starting with their standard Fundamental Handbooks to the latest Green Standard 189. In between, ASHRAE issued six guide books detailing measures to achieve the 30% energy savings over the ASHRAE 90.1 Standard for several types of small buildings namely schools, warehouses, office buildings, retail building, healthcare facilities, and hotels. With the relatively recent inception of the LEED System by the U.S. Green Building Council, as a part of the push for green, energy jumped to the forefront. Owners are eagerly evaluating the possibility of getting their new buildings classified in accordance with the LEED system. Background: Systems, in commercial buildings, that consume most of the energy, are the lighting systems (approximately 33%), the HVAC systems (approximately 32%), and the plug and process loads (the rest). In other words, if a building owner pays $10,000 in energy (electricity and fuel) per month, that amount can be simply broken down into: $3,300 for building lighting, $3,200 for the HVAC system consumption and the rest for the other miscellaneous loads. Therefore if there is a chance to reduce the consumption of energy by increasing the efficiency of the HVAC and the lighting systems say by 30%, then the monthly payment for energy will drop to $8,140. A saving of 18.6% will be achieved. The heart of the matter: The question becomes: How can a building owner increase the energy efficiency of the HVAC and lighting systems in their building? The simplest answer to this question is to start with an energy audit. Energy audits expose all potential inefficiencies in the building energy consuming systems, which include building lighting and HVAC systems. The lighting systems should have efficient fixtures and ballasts, and lighting controls should divide the entire system into smaller zones so that if the switch is engaged, not the entire building or floor is energized. Motion sensors can save a lot of energy if implemented in areas that are not occupied for long periods. The HVAC system is where most inefficiencies can be found. Old boilers are inefficient by nature of their manufacture and with time, due to fouling on the tubes, whether fire-tubes or water-tubes. Their controls are rough at best and most likely the sequences of operation that they follow are old and do not capture any benefit of the new controls systems that track capacity to load. Another issue is the pumping system. Is it old constant flow system with three-way valves? Or is it variable secondary with constant flow primary, which is more efficient? Or is it the most efficient variable primary system? The use of VFDs was prohibitively expensive few years ago. These days, VFDs costs are a little more than a standard starter. Many companies are using VFDs, even on constant flow systems, to prevent the bump that the electrical system gets with the start of that pump. The same applies to air conditioning systems. Since the most energy consumption in an air conditioning system in the northeast is the fan. Constant volume wastes a lot of energy. For example using of a constant volume fan with 10 hp motor running 24 hours a day, 365 days a year will consume 65,700 KW/year. The same fan with the same motor if transformed into a variable volume system will consume 49,275 KW/year. The saving is 25% approximately. Motors are another source of energy inefficiencies. There are several grades of motor efficiencies that can be considered for the existing application to reduce energy waste. Old thermostats are good in maintaining a set temperature in any space. New programmable thermostats that can be programmed for four time slots a day and have the programming possibility for 7 different days will reduce the total energy consumption considerably and hence save sizeable amount of money by maintaining 28 different temperatures a week for the same space to accommodate occupied and unoccupied as well as night settings. Conclusion: Buildings do not have to be in-efficient. They can be made to be as efficient as their systems can ever be, or as efficient as new systems, with replacing their old systems that had over lived their useful operating life. A simple energy audit is a very inexpensive tool that will be performed in a very short time and will definitely help building owners uncover many money sinks that are afflicting their buildings and wasting their resources. Building owners with the help of the energy audit can very easily plug those sinks and put their resources to better uses. George Awwad, PE, CEM, LEED AP, CBCP, is department head of Falcon Energy Consultants, Bridgewater, N.J.