Updated: Oct 3, 2022
I’m publishing a series of posts designed for energy engineers to think beyond the typical energy retrofits; and build meaningful projects for their clients. This post is a quick summary or checklist of the areas of impact to look for in creating a comprehensive project that delivers benefit to your customer, profits to your company, and increases your value to any Energy Services Company (ESCo).
Renewable energy includes solar electricity, solar heating, wind energy, wood biomass, biofuels, and waste gas heating or generation. I may have missed a few. Renewable energy is often the best option to reduce negative impact on the environment. These options often cost more money than other energy sources, but not always. In some cases, there may be options to install solar panels to provide renewable energy and reduce peak demand. In other cases, forest waste that has no other use can be used as a heating source. In these cases, renewable energy may provide a net cost benefit.
Lighting has evolved from candles to gas lights to incandescent lights to fluorescent lights and now to LED lights. Each evolution of lighting has created more efficient conversion of energy into light. Retrofitting lights to the latest evolution will increase lighting quality and reduce electricity usage and electricity demand. If the client has a predominant cooling load, lighting retrofits will also reduce HVAC energy required to cool the building.
Heating, Ventilating & Air Conditioning (HVAC)
This category is quite large and includes the energy required to heat, cool, and ventilate a building. Here are some sub-categories:
Variable Speed Drives: Identify large motors (greater than 1-hp) for variable speed drive retrofits. All pumps and fans can be slowed down during lower periods of demand to dramatically reduce air distribution and water distribution energy.
Indoor Air Quality: A building can either be under ventilated or over ventilated. Ventilation has a great impact on the amount of energy used to heat or cool a building. When the building is fully occupied, fans should be providing sufficient air for building occupants. When the building is partially occupied, ventilation can be reduced. This can be done with occupancy schedules or with carbon-dioxide sensors that control ventilation to maintain a CO2 setpoint.
Cooling Plant: Cooling plants can be chillers that cool water that is pumped to air handling units, direct-expansion cooling for individual cooling units, or evaporative cooling in arid climates. There are too many types of cooling plants to mention in this checklist. However, its important to understand what role the cooling plant plays in energy consumption of the building. In hot climates or high process loads, cooling will be the major contributor to energy usage. In cold climates, cooling may be non-existent.
Free Cooling: As it turns out, buildings require cooling at outdoor temperatures that are greater than the building balance point. Light internal heat gain buildings have a balance point of 60 F; while heavily loaded buildings have a balance point as low as 35 F. When the outside air temperature is cold and parts of the building need cooling, you can use cold air outside to cool your building instead of using energy to create cooling. In arid climates, you can use evaporative cooling to cool water or air down to 25 F below the ambient air temperature. As simple as free cooling is to use, it is often the most overlooked strategy for modern buildings.
Heating Plant: Heating plants are as diverse as cooling plants. A building can be heated with steam, hot water, direct-fired gas, solar heating, and electricity. If you’re in a cold climate, heating energy may be the dominant form of HVAC energy and should be a major focus of your energy audit. Likewise, if the building has high internal heat gain, heat waste from process loads, or is in a hot climate, heating may be a minor contributor to energy consumption.
Building Automation: Automation systems will schedule HVAC systems in unoccupied modes when people are not in the building. This will dramatically reduce HVAC energy requirements. Automation is a dual edged sword. Just because a building has an automation system, doesn’t mean that building is using energy efficiently. If the building automation system exists, it’s a good idea to check out how well it is controlling or not controlling energy consumption of HVAC systems. In many cases, operations of the automation system bypass energy saving measures to reduce the hassle factor of operating the building.
Heat Reclamation: Many mechanical processes generate waste heat that may be used in other parts of the facility. A good example is a grocery store. Grocery stores need to refrigerate perishable foods and frozen foods. Refrigeration compressors must reject their heat. Many grocery stores utilize this waste heat to heat the store space during cold weather; and use the rejected heat to heat water for cleaning portions of the store. In some cases, waste heat may be available from a nearby industrial facility.
Building envelope relates to the roof, walls, windows, and doors. A typical inclination is to be critical of a poorly insulated building and praise a well-insulated building. If a building has single pane windows, an energy engineer will think that they can save money by replacing these windows with double or triple pane windows. The challenge is the balance point of the building. If the building has high internal heat loads (people, equipment, lights, etc.), and it is in a cold climate, then it may benefit from a poorly insulated building envelope. In on the other hand, the building is losing valuable heat, while mechanical systems are attempting to heat the building, improving insulation, and sealing leaks in the building envelope will be a benefit.
As it turns out, electric utilities pay a higher price for electricity when it is in high demand. For this reason, they charge more money for electricity used during these peak periods. Most utilities experience a peak in the middle of a hot day. If your client pays a high electricity demand charge, you can find ways to shift their peak energy usage. Here are a few ideas.
Ice storage cooling – Make ice at night and melt the ice instead of running mechanical cooling during peak periods.
Electric Generators – Run emergency generators or other electricity generation during peak periods to reduce peak electricity usage of the building.
Curtail Loads – This is a tactic to reduce fan, pump, and other non-critical electric loads when the building is experiencing a peak. This can only be done for non-critical loads.
Absorption Cooling – Absorption chillers use heat to make chilled water. Since they don’t use electricity, they can be used during peak periods to provide cooling instead of electric chillers.
Solar Electricity – If peaks occur during hot summer days when the sun is out, solar panels may be a natural peak shedding solution.
Off-Peak Charging – Charging any battery devices during non-peak hours will reduce unnecessary peak electricity consumption.
If the client doesn’t pay a peak demand penalty, then seeking out peak shedding tactics is a waste of time. Otherwise, peak shedding can be a major money saver without reducing energy consumption.
Being aware of energy rates for any energy audit. The cost of electricity, natural gas, water, sewer, and any other utility will determine what retrofits will work best in each situation. As our electric grid is getting more taxed, electric rates may become much more complicated. Natural gas rates have cycled from $0.10 per therm up to $2 per therm in a short amount of time. Be aware of the utility rates your customer pays, what utility rates may be available to them, and how utility rates may change in the future. Plan your energy solutions accordingly.
Water conservation is often overlooked… because it’s not electricity or gas. However, water can be a large expense for many facilities and industrial sites. First, understand that water utilities have three primary categories: 1) Non-Potable; 2) Potable; and 3) Sewer. Here are a areas to consider:
Sewer Credit Meters: The highest part of a water bill is the sewer portion. Most irrigation water, cooling tower makeup water, and swimming pool make up water does not end up in the city sewer system. This means that you can install credit meters to reduce this portion of your client’s water usage from the water bill.
Non-Potable Water Use: Potable water is for human consumption (cleaning, drinking, etc.). There are many other sources of water for irrigation and other high use water areas that do not require potable water and cost much less.
Irrigation Efficiency: The largest portion of any facility’s water bill is irrigation. There are many solutions to reduce water consumption in irrigation systems that did not exist before 2010.
Weather based sprinkler control systems
Sprinkler coverage audits and retrofits.
Appropriate watering times for different plants.
Water reducing devices: Low flow toilets, urinals, flush valves, faucets, showers, and any other water using device can reduce water cost by 50%.
Make sure that you know how your client pays for water before you consider water conservation strategies.
Another area that is overlooked is waste management. Most places generate a substantial amount of waste that is not necessary. In one case, a colleague of mine noticed that a school district was using paper plates and plastic utensils in their cafeteria. They said they did this because they couldn’t afford a dishwasher. He recommended a new dishwasher that would reduce a very costly waste stream as part of this project. It was a win/win/win/win… for the customer/environment/budget/company.
Most modern computers use efficient power supplies and effective power management software. However, not everyone uses this software or owns modern computers. This computer load can be a major factor in electricity usage, demand, and cooling load.
Most industrial facilities consume resources in a much different way than buildings. Do not be afraid to learn about your client’s industrial processes. While they are experts at their process, you must show up as the energy expert who is viewing their process from a completely different perspective. Every industrial audit I’ve conducted, I identified an energy use that was costing my client money that they had never known about before. In every case, I was not an expert in their industrial process. Please do not leave this stone unturned if you are auditing a specialized industrial facility.
Hopefully, this gives energy engineers and business development executives beneficial scope development insight. Stay tuned… I plan to add several more posts to this series to help you grow the size of your energy projects and provide more comprehensive service for your clients.
About me. I have been actively engaged in the energy efficiency, renewable energy, and energy conservation industry all my professional career from 1987 until now. I was a licensed Professional Engineering in six states and a Certified Energy Manager (CEM). I worked as a sales executive, energy engineer, sales manager, and entrepreneur. I started, grew and sold my own Energy Service Company (ESCo) called Ennovate Corporation (1997 to 2013). I now coach business owners, engineers and business development executives in the energy efficiency industry.