Cooling load simulation according to VDI 2078
In the cooling load simulation according to VDI 2078, the building is also simulated hourly according to the procedure of VDI 6007, but in contrast to the free simulation, standardized climate data are used. The calculation of the cooling load is done dry according to the VDI guideline, i.e. an increased cooling load due to condensation at high humidity is not taken into account.
Climate zones
For the use of the cooling load calculation, Germany is divided into five different climate zones according to the TRY (Test Reference Years) of the German Weather Service. These are shown in the map on the left.
Standardized climate data
The climate data used for the calculation of the cooling load are formed for 5 different climate zones from the averaged climate data of these zones. The climate data consist of a transient period, in which the same sinusoidal course of outdoor temperatures and irradiation is specified for 14 days every day. This period is used to settling the building.
This is followed by five further days with a rising temperature curve. This is followed by the day with the highest temperature and the strongest irradiation. Since the temperatures are highest here, this day, the 19th, is always the day with the highest cooling load in this period of climate data. Therefore the design day is always the 19th day of a month. After that, the calculation for this month is aborted and the calculation starts again with the standardized temperatures of the next month. This is done for the months April to September inclusive. The program then displays the day on which the highest cooling load occurred. Usually this is July 19 or August 19. This type of calculation is intended to ensure that the room air temperatures calculated in this way produce a maximum value that is not exceeded with the actual test reference year.
Further boundary conditions
For the calculation of the cooling load, internal loads caused by e.g. devices, persons etc. must be considered in addition to the climate data. User profiles are entered in the English tabs. For the cooling load calculation the same user profiles are used as for the free simulation. However, instead of the calendar, the first profile is valid for working days and the second profile for weekends (the number of working days per week can be set via a button).