Sustainable Clark

Consumption of Thermal Energy

Benchmarks

Total thermal energy consumed in million BTUs

Energy consumed per square foot of campus buildings

Background

The core campus is heated by steam and hot water generated from our central boiler plant. The steam is transmitted across campus through a network of underground pipes that service heating systems and radiators in 18 of our major campus buildings. Three high-pressure steam boilers capable of producing 41,800 pounds of steam per hour are located in the basement of Jonas Clark Hall. The boiler plant uses natural gas as its fuel source, augmented by waste heat from the cogeneration combustion exhaust.

In addition to the steam-generating boilers, Clark University's cogeneration plant produces 2,000 kW of electricity. Cogeneration captures "waste" heat produced in generating electricity as a source of thermal energy. In the Clark cogeneration plant, the waste heat comes from jacket water used to keep the engine at the correct temperature, much like the radiator cooling system of an automobile. The jacket water is used to supply a hot water loop that heats seven of the major buildings on campus, with the radiators in these buildings removing heat from the loop. In the summer months, the same underground water loop is used for chilled water from a chiller plant on the roof of Goddard Library as a way of air conditioning these buildings. The combustion exhaust from the cogeneration plant engine is also used as energy in the form of a waste heat boiler positioned between the engine and the exhaust stack and feeds steam into the main power plant.

Heating and cooling are controlled through fully-monitored, centralized energy management software. A network of temperature gauges and sensors provide real-time data. Interior building temperatures are adjusted automatically and overseen manually to ensure occupant comfort and thermal energy optimization throughout the core campus buildings in accordance with policy.

Heating and Cooling Policy

Clark University policy is to set temperatures at 78 degrees for cooling, 68 degrees for heating and 130 degrees for domestic hot water. During the heating season, the temperature in residence halls and houses will be set at 68 degrees during the day and 65 degrees at night. Academic and office buildings will be set at 68 degrees during the day and 62 degrees at night. Unoccupied buildings, which are buildings not in use, will have a temperature of 55-60 degrees at times such as semester breaks and any holidays numbering three days or more. The daytime temperature setting refers to 6:00 a.m. to 5:00 p.m. on weekdays for academic and office buildings and 6:00 a.m. to 10:00 p.m. for residence halls and houses throughout the week. During weekends and holidays of two days or less, temperature for office and academic buildings will be set at 60 degrees.

Improvements

Clark takes deliberate action to reduce thermal energy consumption on campus. The Lasry Center for Bioscience, which has been awarded Gold LEED certification, utilizes "heat wheel" technology in the mechanical design. Air-lock doorways in many campus buildings reduce heating and cooling losses. Campus buildings not on the central plant steam heating loop have energy efficient boilers, while domestic hot-water heaters across all of campus enable the University to operate in September and October without starting the main boiler plant. Integration of energy efficiency improvements into all renovation projects on campus facilitates improvements.