Develop a Radiant System Module for the Simulation and Analysis of Spaces and Systems

Develop a radiation exchange module The proposed module will provide the basic algorithm and equations to accurately model whole building radiant energy as it affects comfort, demand for HVAC, and energy use. The module will be demonstrated by coding it as part of a publicly available building energy simulation model (e.g., TRNSYS, DOE-2, EnergyPlus). The proposed module should handle the following items: 1. Short wave radiation. 2. Long wave radiation. 3. The interaction between the three modes of heat transfer.

Surface Radiation
The method for the proposed module could be based on considerations that take into account the infinite number of reflections that occur between surfaces - as used in indirect lighting calculations. However, it has already been stated that long wave radiation depends on surface temperature, so the radiant exchange can be de-coupled from the conduction and convection calculations. The reason is simple, the explicit finite difference formulation makes use of the current state to predict the future, so all that is necessary is to obtain current values of long wave radiation incident on each surface and determine how this is reflected throughout the space. The magnitude of the long wave radiation depends upon the surface temperature and so it is necessary to link the two.

Radiant System Module
The radiant system module and other supporting routines will extend the current capabilities of the ASHRAE Primary and Secondary toolkits (developed under the supervision of Technical Committee 4.7, Energy Calculations). The module will be capable of modeling low temperature hydronic systems (floor, ceiling and wall) as well as electric powered systems, thermal comfort assessment criteria (Fanger, Pierce 2-node, KSU 2-node etc.). The application will integrate new modules with existing toolkits to allow comparison of thermal environments for radiant systems and some limited number of forced air systems. The simple environment to run the application will have a limited amount of input for single room (the emphasis to be on a single room environment under „load calculation conditions).

Radiant Systems and Operation
The module should be capable to simulate different types or combinations of radiant systems such as ceiling systems which could be electric driven for heating, hydronic systems for heating and cooling, hydronic embedded systems for heating and cooling. The module should be c apable of simulating the operation of the radiant systems described above. Operation options should include changes in electric power and operating schedules for ceiling panels, changes in supply and return temperatures and operating schedules for hydronic embedded systems. The module should be proficient in simulating the radiant effects of a space created by the space envelope and conditioning systems employed by the space to maintain comfort conditions. The module must be capable of simulating user input heat transfer coefficients for different surfaces.

Budget Range: $155,000 may be more or less as determined by value of proposal and competing proposals.

Scheduled Project Start Date: April 3, 2009 or later.

All proposals must be received by December 19, 2008.

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Technology #159