How can energy storage help your commercial building?
July 25, 2016
As a facility manager, you've likely you've heard of thermal energy storage. It is an air-conditioning system that stores locally generated energy in the form of chilled water or ice. Yet what do you really know about energy storage and is it right for your building?
Chiller plants have life expectancies of 25 years. Older chillers that are in poor condition, or have capacity or inefficiency issues or machines with banned refrigerants must be replaced or upgraded. Given that lifespan and refrigerant issues, most facility managers are likely to conduct a chiller plant retrofit at least once during their career. A retrofit is a large undertaking and since retrofits are not done often, facility managers must rely on the expertise of equipment manufacturers and consulting engineers. For successful implementation, local representation is key along with great customer support. So when that time comes you need a team that is going to listen and work with your budget to solve your problem quickly and effectively.
Now there are several options out there for retrofits. Do you just go with a like for like chiller replacement? New chillers are more efficient, meeting new and higher refrigerant and energy efficiency standards. Advances in controls, variable speed drives and thermal energy storage provide you with more flexibility to optimize comfort and savings in a transformational electricity market. While, a simple chiller replacement may seem the most simple & economical choice, a thermal energy storage system can prove to be a better investment over the life cycle of the new equipment. There are two main reasons. First is to cut cooling costs by taking advantage of cooling system improvements and of electricity market pricing opportunities. The second reason to consider energy storage is for environmental & grid stewardship.
Thermal energy storage can solve many other building concerns in addition to saving money and being good stewards of our environment and electric grid. Thermal energy storage can help control humidity, provide back power and resiliency, allow participation in demand response programs, offset cooling tower usage and limit maximum power demands.
Similar to an ice machine, one technology of thermal energy storage "ice storage" stores energy in the form of ice. The energy is stored in the form in which it will be used eliminating energy wasting energy conversions. The ice never leaves the tank. Using conventional piping and pumps, heat is simply transferred from the warm building to the melt the ice. The melted ice is used for occupant cooling.
Cut energy costs
Energy costs is the initial reason that facility managers choose ice storage. Utility demand skyrockets during the day for commercial buildings because commercial buildings are using peak on demand air conditioning systems. This causes a peak demand charge, which can double or triple energy prices depending on the season and area. According to the Stanford Energy Club, facilities consume 71 percent of total electricity in the U.S. and 40 percent of which is drawn during peak demand hours. The main culprit? Your electric air conditioning!
At night, during off-peak hours, the inverse it true. Electricity is more affordable at night because demand is down. Commercial AC systems are rarely run at night. With ice storage, buildings can capture their daily cooling load at night in the form of ice and release it the next day instead of drawing from the grid during times of peak demand. This vastly reduces the utility bill, as the peak demand charge is reduced.
Case in point
In Philadelphia, a commercial building at 1500 Walnut Street struggled to maintain its old HVAC system. It was falling apart due to age and excessive use, and tenants were leaving because of it. The building owner vetted multiple companies vying to install, though he settled on IceBank thermal energy storage after learning it was the same exact price as the old infrastructure.
The results were fast. It took just two years to receive full payback on the expense. This came from $40,000 in monthly savings through reduction of peak demand use and demand response savings of $10,000 per year.
"This is found money," Gene O'Donnell, building manager, said. "We don't need one square foot of space in this building to make this money, and the tenants in this building see no change at all."
Go green
Ice storage is also key in reducing greenhouse gas emissions. As an intelligent, green technology, ice storage gains crucial LEED credits and helps take a zero energy building (ZEB) off the grid.
Seeing as ice storage draws from the grid during off-peak hours, ice storage helps facilities produce fewer carbon emissions. This is because of how pollutant peaker power plants are for the environment. Facilities dictate when or even if older, more polluting power plants come online to support grid demand.
"Ice storage gains crucial LEED credits."
For some facilities, the answer is purchasing on-site renewable energy resources. However, renewable energy is not adequate.
The idea of a ZEB is to export as much energy as you import. But what happens when the sun doesn't shine? Renewable generation is inhibited, which forces the complex to draw from the grid. When this occurs during the day-time peak demand hours, the ZEB is contributing mightily to pollution through the fossil fuel plants it's drawing its energy from.
Being able to avoid peaking plants is essential for reducing emissions. Storing excess renewable energy is key in shifting away from grid reliance, maintaining consistent power production and keeping a higher percentage of renewable energy on-site. Ultimately, ice storage is where the discussion is shifting toward in terms of ZEB and LEED certification due to its ability to reduce environmental impact.
So is thermal energy storage right for your building? With such vital cost and environmental benefits, ice storage is a retrofit option that cannot be ignored. Click here to see if ice storage is right for your building.
