The Cooling Load Temperature Difference (CLTD) values available in the literature for using the simplified CLTD method only apply to rooms under constant indoor air temperature. Due to this limitation, the present paper extends the application of this simplified approach to cooling and heating loads estimation of rooms with daily and weekend setback and setup thermostats, and introduces the term thermal load temperature difference (TLTD). To generate the values of TLTD, a transient heat transfer model, and the corresponding numerical tool, has been developed to predict the thermal behaviour of multilayered walls and flat roofs. The sol-air temperature concept is used. The internal thermal capacity of the room is assumed negligible. The TLTD evolutions have been generated for a wall and a roof, of high mass construction, with setback and setup thermostats in winter and summer scenarios. The periods in which the room is unoccupied have been taken in due account. The TLTD evolutions allowed the estimation of: the energy transferred at the inner surface and the maximum thermal load. Among the cases studied, the relative difference found in the energy transferred through the sunlit envelope, roof or wall under summer conditions, is about 20% when the temperature control strategy is changed from A to B.
|Journal||Applied Thermal Engineering|
|Publication status||Published - Mar 2013|
- External envelope
- Thermal load temperature difference
- Setback and setup thermostats