We\'re requesting confirmation for a proposed modeling methodology to simulate humidity control in the baseline system. Our project is a multipurpose facility that includes warehouse, manufacturing, laboratory and office spaces. The manufacturing portion of the building comprises roughly 45% of the overall facility. Numerous energy saving measures have been incorporated into this facility and we believe that our project meets the intent of this credit. However, the manufacturing portion of the facility requires some unique parameters, primarily humidity control, that the ASHRAE 90.1-2004 baseline system, system 3 PSZ-AC, is unable to simulate through normal means. The prominent standards (Issued by the U. S. Food and Drug Administration and the International Society of Pharmaceutical Engineers) that spaces of this nature are designed to are as follows: 21 CFR Part 210 - Current Good Manufacturing Practice in Manufacturing Processing, Packaging or Holding of Drugs; General 21 CFR Part 211 - Current Good Manufacturing Practice for Finished Pharmaceuticals ISPE Design Guidelines - Volume: 3 Sterile Manufacturing Facilities These standards regulate the practice of how products are to be manufactured and the environment the products are to be controlled within. Four parameters to be controlled of a critical nature are Air Volume, Temperature, Pressure and Humidity. The air volume, temperature, pressure, and humidity need to be controlled to conditions proper to the production of the drug and need to be consistent to insure consistent quality of the drugs. Humidity control is an FDA requirement, but it is a significant contributor to energy consumption for the facility. Requirements for air volume, temperature, and pressure have been consistently applied to both the baseline and proposed energy simulation cases. Humidity control to a level of 45% can only feasibly be met and maintained year round by employing "reheat" control wherein the air is cooled, to 50F, to remove moisture and then "reheated" to maintain space temperature. It is for this reason reheat is being utilized and the commensurate energy consumption is greater than that used by a "cooling only" mode of operation. Uncontrolled humidity can cause degradations in the product that are often responsible for inconsistent quality and are cited by the FDA as such. Humidity control through reheat was approved in the CIR dated 6/19/2007. According to the CIR ruling, "Humidity control requirements should be the same as in the proposed building, even if it requires reheat to be modeled with that system type." Because the baseline system (system 3, PSZ-AC) is unable to meet/simulate the humidity control required, we are requesting confirmation for the following methodology to model the humidity control in the baseline simulation. First, the energy required to dehumidify (cool) the air from 58F to 50F must be added to the baseline energy simulation. The baseline model has shown that 58F will satisfy temperature requirements for these manufacturing spaces. Second, the additional energy required to reheat the air from 50F to 58F must be included. Please confirm whether or not the proposed steps are acceptable to model reheat for this facility.
The applicant is requesting the use of an alternative modeling strategy in order to achieve specific temperature, air volume, pressure, and humidity requirements for a climate controlled manufacturing environment. The request is based on the assumption that the baseline system type for the manufacturing spaces is packaged single zone and the belief that the simulation program is unable to meet the space humidity requirements with this system type. If the space is being conditioned to meet the requirements of the manufacturing process and not the requirements of occupants, then the load might be classified as a process load. If this is the case, the approach detailed in a CIR ruled on 5/27/08 should be followed. Specifically, the baseline mechanical system serving a process load is of the same type and has the same controls as the proposed design. The efficiencies of the components of the baseline system are minimally-compliant with ASHRAE 90.1 Chapter 6. The proposed design efficiencies are as-designed. To account for energy savings for mechanical system improvements (or other unregulated components associated with process loads) that go beyond what is typically done for the application, an exceptional calculation method can be followed.