AL-2508 (RP 208) -- Occupant Acceptability of Eight-Hour-Long Temperature Ramps in the Summer at Low and High Humidities PDF

Previous studies have shown (I, 2) that slow rates of temperature change (0. 5°C/h) from optimal comfort conditions are almost undetectable by occupants from traditional constant temperature conditions. In our previous 4-hr-Iong tests (1) thermal acceptability remained above SO% when temperature deviations from optimum were 20 C or less. Allowing the inside temperature of a building to drift with outside conditions and internal loads has important energy saving (3) and load shifting implications for both new and old buildings, prOVided the environment remains thermally acceptable to the building's occupants.

This paper reports on occupant responses to temperature drifts during an S 1/2-hr working day. Since the energy and cost saVings potential of temperature drifting appears to be largest during the summer (3), clothing and drift conditions appropriate for this season were chosen for these tests. Experiments were conducted where the temperature rose slowly throughout the day from a cool initial condition. Using a similar strategy, a building could be cooled at night with outside air and refrigeration when the air is cooler and when electrical demand and rates are lower and COP's are higher. Then dur'ing the day, the building's temperature could be allowed to drift upward with reduced refrigeration or without refrigeration. Many variations of this theme are possible such as using stored chilled water, increased building mass, and/or a temperature ramp control system.