We are modeling a solid waste transfer station facility and a materials recovery facility for the South Bayside Waste Management Authority in San Carlos, CA. The two facilities for the project are unconditioned spaces; they are not heated or cooled. In regard to the ASHRAE 90.1 modeling parameters under Energy and Atmosphere Credit 1, where heating and cooling systems are required to be modeled for both the proposed and baseline models (even when such systems do not exist) we propose to use two strategies to most accurately represent our facility and comply with the accepted procedure for modeling. Firstly, we propose to model the thermostat set points such that those systems are not activated. For example, with a cooling set point of 95 degrees F, the cooling equipment will remain idle and no energy use will be modeled. ASHRAE 90.1 does not specify where thermostat set points should be set; it only requires that the set points be the same for the proposed and baseline models. Setting them such that the equipment is not activated will accurately measure the energy use, since no heating and cooling will be provided for the facilities and therefore no energy will be used for heating and cooling. We feel this method meets the intent of the credit, since no heating or cooling system could possibly use less energy than we propose to use. Is this acceptable? Secondly , the materials recovery facility contains a small number of people in relation to the square footage of the building. These occupants will all work in a localized area along the production lines that sort the solid waste stream. If we provide spot cooling and heating for the comfort of these workers, we propose the energy used by these systems be modeled as process energy. Heating and cooling systems for this purpose will not be used to heat or cool the space, but to provide comfort for the workers on the line by immersing them in an airstream that is cooler or warmer than the ambient conditions. These systems will be idle when workers are not present and will not be capable of maintaining a thermostat set point in the whole of the large, mostly unoccupied footprint of the building. As process loads, the systems will be modeled to operate on the same schedule as other process equipment, such as conveyors and sorting machinery. Is this methodology allowable?
The first strategy discussed by the project team proposes modeling setpoints in unconditioned spaces so that the system is not activated in order to meet the requirements of ASHRAE 90.1.2004 Table G3.1 #10 and yet model the actual system characteristics. This approach is acceptable, given that the systems are modeled identically in both the proposed and baseline cases. However, for conditioned spaces (see sub-zone suggestion below), the setpoints should be modeled to accurately represent the conditions in the space. The second question proposes that personal/localized cooling and heating systems are represented as process energy rather than HVAC energy. This approach is not acceptable for the achievement of this credit. ASHRAE 90.1-2004 defines process energy as "energy consumed in support of a manufacturing, industrial, or commercial process other than conditioning spaces and maintaining comfort and amenities for the occupants of a building" (see Definitions). The project team might consider creating a conditioned sub-zone for the localized area that mimics as closely as possible the spot heating and cooling provided (in terms of setpoints, air temperature and/or ventilation rates), based on guidance provided in ASHRAE 90.1.2004 Table G3.1 #13. Applicable Internationally.