Introduction
Introduction
Thermal Energy Storage (TES) is a well-recognized energy management tool that transfers a large portion
of the electricity required for air conditioning from high-price, on-peak hours to low-price, off-peak
hours. TES systems using ice storage allow an air conditioning system to operate during off-peak hours,
transferring clean and less expensive electrical energy into stored energy. The stored cooling energy in
the ice is later delivered to provide air conditioned comfort during on-peak hours when electricity prices
are higher and electrical power is limited, less reliable, and more polluting.
Traditionally, TES systems have benefited only large energy users, such as hospitals, large office
buildings, college campuses, and schools. The ICE BEAR
®
30 unit was developed specifically so that
buildings with small air conditioning and power requirements can receive comparable energy and
environmental benefits using a variety of packaged rooftop and split system air conditioners.
Thermal Energy Storage systems address the electrical system problems that other energy efficiency
measures do not address, in particular, resource allocation to meet the supply and demand of electricity.
Peak energy costs and emission concerns will continue to be a problem for the foreseeable future. Many
utilities offer rate structures that encourage energy management systems such as TES. Time-of-Use
(TOU) rates have become standard tariffs offered by many utilities. The substantial energy price
difference between on-peak and off-peak periods provide a significant financial incentive for using some
form of thermal energy storage. The higher costs of peak electricity reflect the pollution mitigation costs
associated with the higher emissions rates of peak energy generation.
A growing number of states are adopting energy efficiency standards above and beyond the federal
appliance standards. For example, the California Building Energy Efficiency Standards “performance
approach” uses a modified ASHRAE 90.1 methodology to establish the allowable energy consumption of
a proposed building project as compared the energy consumption of a minimally-compliant of a similar
building of similar occupancy, construction type and location. California’s Title 24 Standards estimate a
proposed building’s energy budget using an hourly time-of-use methodology and assigns a unique source
energy multiplier for each hour of the year to arrive at an estimate of the amount of source energy
required to provide the energy needs of the proposed building. The utility’s complete electricity network
costs, such as generation, transmission and distribution, and environmental mitigation are estimated for
each hour of the year establishing a Time Dependent Valuation (TDV) of energy. The resulting
calculation estimates a more accurate hourly cost and environmental impact of building energy
consumption. An hourly TDV multiplier for each of the state’s 16 climate zones translates site energy use
into a more accurate approximation of total source energy costs. When this TDV multiplier is applied to
an Ice Bear unit and conventional air conditioning systems of the equal capacity, the ice storage system
has as much as 22 times more TDV energy savings potential during peak periods.
Utility cost savings are clearly just one of the benefits provided by the Ice Bear unit. Ice storage plays a
significant role in obtaining certification points for the United States Green Building Council’s LEED
®
program. The Ice Bear unit’s superior cooling comfort, reliability, and reductions in the energy budget
can earn one to five Energy and Atmosphere Credits and up to 6 credits in other categories.
Ice Bear
®
30 Unit Application Guide
1