Energy efficiency is always beneficial for buildings since it translates into a direct reduction of operating expenses. This is especially true for electricity bills in large cities. However, consider that energy efficiency is an investment: capital is used upfront to achieve a greater long-term benefit. Just like investors seek advice to find the best way to allocate their capital, property owners should determine the best approach to implement energy efficiency before proceeding with the actual project. The services of a qualified energy consultant or MEP engineering company can be of great help.
Equipment manufacturers often offer energy efficiency advice along with their product offerings, and while it is technically accurate, it tends to focus on their products in isolation from other building systems. For example, an air conditioning supplier is unlikely to suggest building envelope, space heating and lighting improvements to improve overall performance. On the other hand, a consulting firm will take a whole-building approach without focusing on a specific system only, allowing them to suggest the best solution.
Consulting Offers Technical Accuracy
Equipment vendors often follow a “recipe” approach when dealing with energy efficiency, offering you a product and indicating percentage savings achieved with to conventional systems. As a result, the offered savings are based on what is commonly found in buildings and may not always match your site conditions. In other words, the approach followed by suppliers starts at the solution and how it fits a specific building.
Also consider that equipment providers have sales targets to reach, so they are unlikely to suggest measures that will reduce the monetary value of their offering. For example, if your current cooling load is 200 tons of refrigeration, a chiller vendor will probably suggest a 200-ton unit with high efficiency right away, instead of helping you reduce the required capacity.
Energy consultants follow a different approach. Following with the example of the 200-ton chiller, they will first assess factors that affect your cooling load, such as:
- Lighting: LED products emit much less heat than their incandescent, halogen, fluorescent and HID counterparts. Replacing one lamp does not make a great difference, but the effect is significant for a large building with thousands of them. Replace 1,000 fluorescent fixtures consuming 120W each with 50W LED fixtures, and you have effectively reduced lighting heat by 70 kW (19.9 tons of cooling).
- Building Envelope: Poor insulation and air leaks increase unwanted heat transfer into and out of the building, driving up both heating and cooling loads. Energy consultants evaluate these aspects before suggesting an equipment upgrade.
- Automatic Controls: One aspect of energy efficiency is upgrading to equipment that meets building needs while consuming less energy, but using it optimally is equally important. Automatic controls ensure that no equipment operates for more time than necessary, and can also optimize output if the equipment allows it (dimmable lighting, variable-speed chillers, air handlers with variable-frequency drives, etc.)
In this case, perhaps you will only need a 160-ton chiller after improving lighting systems and the building envelope. Assume the existing 200-ton chiller has an efficiency of 0.8 kW/ton, with a power consumption of 160 kW, while the upgrade operates at 0.55 kW/ton. The respective power drawn by new 200-ton and 160-ton units would be:
- New 200-ton chiller power = 200 ton x 0.55 kW/ton = 110 kW (31% savings)
- New 160-ton chiller power = 160 ton x 0.55 kW/ton = 88 kW (45% savings)
Assuming 2,400 hours of use per year and an electricity price of 16 cents/kWh, the first chiller consumes 52,800 kWh more per year, equivalent to $8,448 in power bills.
MEP Engineering Consulting Allows an Accurate Financial Analysis
After professional MEP engineering consultants carry out a detailed energy audit for a building, it is possible to know the upgrade cost and resulting savings with a high degree of accuracy, and this information can then be used for a financial analysis. Key decision-makers often have a professional background in business, and would likely prefer to see metrics such as net present value and return on investment, while kilowatt-hour and percentage savings are of more interest for technical personnel.
The annual savings projected after an energy audit are also useful when property owners seek loans for their building upgrades. With detailed information on how upgrades will perform, they can determine if the project can fully cover debt service with energy savings. The consulting service itself can also be considered an investment: Professional savings are paid upfront, before proceeding with a project, to ensure that the best possible performance is achieved.
Legal Requirements and Code Compliance
If you are considering a renewable energy system, consider energy efficiency first. When a building optimizes energy use, a given renewable generation capacity can meet a larger portion of energy needs. For facilities where the plan is to use 100% on-site generation, the required capacity is reduced if energy efficiency is addressed first. From the initial consultation to the finished result, you should have an MEP engineering professional to guide you through this process.