California Energy Commission (CEC) authorities are delaying the implementation of the new Title 24 Energy Conservation Code by six months. The CEC believes that postponing the effective date is necessary to allow the industry to prepare for the new standards. This new energy code will have a major impact on new supermarket construction.
Energy Efficiency Standards for Residential and Nonresidential Buildings (Title 24) were established in 1978 in response to a legislative mandate to reduce California’s energy consumption. The standards are updated periodically to allow consideration and possible incorporation of new energy efficiency technologies and methods. These standards apply to residential, nonresidential, high-rise residential, and hotel and motel buildings.
New energy-efficiency standards are outlined in Section 6 of California‘s Title 24 building code to include supermarket refrigeration systems. The 2013 Building Energy Efficiency Standards (or 2013 Standards) will take effect on July 1, 2014. Section 120.6 includes the following mandatory requirements for supermarket refrigeration systems:
- Floating head pressure (down to 70°F or lower)
- Remote condenser specific efficiency
- Floating suction pressure
- Mechanical subcooling (liquid subcooling requirements for low temp parallel racks)
- Display case lighting control
- Refrigeration heat recovery (without increasing HFC charge)
Supermarkets affected by these changes include an 8,000 square feet small neighborhood markets, all the way to a 150,000 square feet big box stores. Parallel rack refrigeration systems and distributed refrigeration systems must meet these new requirements.
Floating head pressure requires controls to float refrigeration system saturated condensing temperature (SCT) to 70°F during low-ambient temperature conditions. Condenser specific efficiency sets condenser fan motor efficiency requirements. Floating suction pressure requires controls to set target suction temperatures based on space temperature rather than a fixed set point. Mechanical subcooling requires liquid refrigerant to be subcooled to 50°F or less on low-temperature systems. Automated display case lighting must turn off display case lights during non-business hours. Finally, heat recovery must use rejected heat from refrigeration systems for space heating, with a limited increase in refrigerant charge.
According to a notice from the California Energy Commission, the revised effective date – July 1, 2014 will provide the building industry with full complement of tools to comply with the prescriptive and performance compliance options and sufficient time for training on the use of those tools.
Rajan Rajendran, Ph.D
Vice President, Engineering Services and Sustainability
Emerson Climate Technologies