- Author
- Burch, D. M. | Zarr, R. R. | Faison, T. K. | Licitra, B. A. | Arnold, C. E.
- Title
- Procedure for Measuring the Dynamic Thermal Performance of Wall Specimens Using a Calibrated Hot Box.
- Coporate
- National Bureau of Standards, Gaithersburg, MD Department of Energy, Washington, DC
- Journal
- ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) Transactions, Vol. 93, No. Part 2, 105-119, 1987
- Report
- No. 3060,
- Keywords
- walls; composite materials; heat transfer; measurement; finite difference theory; polystyrene; thermal insulation; reprints | concrete blocks
- Abstract
- An experimental procedure is developed that permits a calibrated hot box to be used to measure the transient heat-transfer rate through a composite wall specimen. In this procedure, a composite wall specimen is installed between the metering and climatic chambers of a calibrated hot box (CHB), and a time-dependent outdoor climatic condition, such as a sol-air diurnal temperature cycle, is generated in the climatic chamber. The metering chamber is maintained at a typical indoor condition and is used as a calorimeter. The transient heat-transfer rate through the wall specimen at hourly time steps is determined from an energy balance of the metering chamber. In the energy balance, the time-dependent heat-transfer rate through the specimen support frame is predicted using a finite-difference model, and the energy-storage rate within the metering chamber is predicted using a semi-empirical model. A dynamic calibration test was conducted to investigate the accuracy of this procedure. A masonary wall, comprised of 4-in-thick (0.1 m) polystyrene insulation and 5.6-in-thick (0.14 m) solid concrete block and having known heat-transfer properties, was tested. Good agreement was observed between the measured-and-predicted-specimen heat-transfer rates, thereby supporting the validity of the energy balance under dynamic conditions.