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Updated and enhanced test reference years (TRY) for computer simulations and for the verification for summer thermal protection

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TRY as part of the EnEV

For the verification of summer thermal protection, the Energy Saving Ordinance (EnEV 2013) refers to a procedure according to the current technical regulation for the calculation of a sufficient summer thermal protection (DIN 4108-2: 2013-02 section 8). According to this, as alternative to the verification based on the sunlight transmission value, a computer simulation is also allowed (see appendix 1 number 3.3 EnEV 2013 for residential buildings as well as appendix 2 number 4 for non-residential buildings). To carry out such calculations, hourly climate data sets – so-called Test Reference Years – are needed, that describe the conditions at the site of the building with sufficient accuracy; rules for choosing these datasets are given within the standard.

TRY 2011 – Mapping of climate change

The test reference year data sets (TRY) that have been regularly used for calculations up to 2011 were mainly based on knowledge from the period before 1980. Because of this, they are not really suitable to represent the radiation- and external temperature conditions for the purpose of a simulation of the interior temperatures in buildings in the summer. Therefore, the Federal Institute for Research on Building, Urban Affairs and Spatial Development in collaboration with Deutscher Wetterdienst (DWD; Gemany’s National Meteorological Service) with funding from the research initiative "Future Building" has carried out a research project which provided useful data sets (“TRY 2011”). Thus the simulations to prove suitable summer heat protection according to the EnEV can be carried out by experts in the intended way.

The current standard DIN 4108-2: 2013-02 is based on the “TRY 2011”; this applies to the method using sunlight transmission values as well as for the method limiting overheat-degree-hours in combination with simulations.

The report as well as the “TRY 2011”-dataset including a handbook are available for free:
>> to the project and the downloads

TRY 2017 – high-resolution datasets for German locations

Advantages of local climate datasets

The “TRY 2011”-dataset still follows the traditional approach: Each location is assigned to one of 15 reference stations; the dataset applied in principle is valid for the location of this reference station. As a first step to adopt the data to the so-called “urban heat island effect” as well as to the difference in altitude between real location and reference station, algorithms were developed with the dataset.

With advanced energy performance of buildings, normally a high share of renewable energy has to be used, mainly environmental heat and solar energy. Especially with solar-thermal and photovoltaic energy, the concurrency between demand and availability of the source play a key role. In order to choose the economically most efficient construction for a concrete building, knowledge is needed about the climate really expectable at the location.
Considering this, the “TRY 2017” are made available in a resolution of 1 square kilometer.

Meteorological basis of the new TRY

With modern interpolation methods – using measured data from terrestrial stations, from satellites and model data – an advanced grid dataset for Germany was created in a first step. The modification of air temperature and humidity due to the influence of urban surroundings and altitude are already incorporated in these data.

In a second step, local TRY datasets were extracted from these primary data. Concerning their basic structure, the new TRY data follow the traditional datasets. In addition to the mean TRY for the present, summer- and winter-extreme TRY are made available for all locations. Projections to illustrate the climate change are shown with the datasets for the future (2031 to 2060).

Due to the combination of terrestrial and satellite measurements of radiation, the datasets concerning radiation got a suitable quality to be used as leading parameter (in addition to the air temperature) for the selection of periods for the mean TRY of the present. The yearly chronological sequence of air temperature and global radiation are correctly shown within the mean TRY for the present time. The short-wave radiation values are sufficiently representative to calculate the energy gains of solar-thermal and photovoltaic systems for a certain location.

The primary datasets can be used for many purposes. They are available with a resolution of 1 square kilometer and cover a timespan from 1995 to 2012. Twelve different parameters are included with a one-hour time step. The datasets are suitable to gain lots of climate indices, such as heat days, summer days, tropical nights, airport reference temperatures, radiation nights, conditions on construction sites and windchill factors. Furthermore, valuable information can be gained concerning question about renewable energies (wind and solar energy) as well as about heat stress. The data can be used to estimate vulnerability and risks and as basis to plan the adoption to climate change of municipalities and of the real estate and housing industry and, furthermore, in the sector of disaster control /-management.

The report as well as the “TRY 2017”-dataset including a handbook are available for free (Datasets presumably by April 2017):
>> to the project and the downloads

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