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IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

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<strong>IEA</strong> SHC Task 38 <strong>Solar</strong> Air Conditioning <strong>and</strong> Refriger<strong>at</strong>ion<br />

Subtask A Report, D<strong>at</strong>e:…<br />

1 Background<br />

The low-energy building of the Technical College in Butzbach has a dem<strong>and</strong> for summer airconditioning<br />

due to high occup<strong>at</strong>ion r<strong>at</strong>es <strong>and</strong> the frequent use of comput<strong>at</strong>ional equipment.<br />

Besides the regular school days the building is occupied throughout the summer season<br />

intensively as well. This fact was determining for the promotion of this project within the<br />

frame of the German <strong>Solar</strong>thermie 2000plus funding programme.<br />

Two ventil<strong>at</strong>ion systems with he<strong>at</strong> recovery <strong>and</strong> a 1,250 m³/h air volume flow r<strong>at</strong>e each were<br />

already installed in the building. These systems were not sufficient in order to remove the<br />

sensible <strong>and</strong> l<strong>at</strong>ent cooling loads in summer. Therefore, a solar autonomous chilling plant<br />

was installed which consists of two absorption chillers of the type Suninverse from<br />

Sonnenklima, Berlin. Each of the chillers has a nominal chilling capacity of 10 kW. They are<br />

driven exclusively by solar he<strong>at</strong> from a collector field of 60 m² aperture area. It consists of<br />

evacu<strong>at</strong>ed tube collectors of the type CPC Star azzurro, Paradigma. In addition, the<br />

ventil<strong>at</strong>ion units were extended by cooling coils. Furthermore, chilled ceilings <strong>and</strong> a cooling<br />

shaft were installed. The area which is air-conditioned comprises 335 m².<br />

<br />

2 System Design<br />

The Fraunhofer ISE supported the preliminary planning by carrying out simplified system<br />

simul<strong>at</strong>ions. With the help of the simul<strong>at</strong>ion results estim<strong>at</strong>ions could be given for the<br />

dimensioning of the system. The vari<strong>at</strong>ion of the building simul<strong>at</strong>ion, which considers an<br />

external shading device, leads to estim<strong>at</strong>ions on the peak cooling loads (sensible <strong>and</strong> l<strong>at</strong>ent)<br />

of more than 20 kW. The sensible cooling loads often showed daily peaks of about 15 to<br />

20 kW. As the type of chiller was almost already decided (Suninverse, 10 kW nominal<br />

chilling capacity) the results supported the install<strong>at</strong>ion of two absorption chillers.<br />

A simplified scheme of the complete air-conditioning plant of the Technical College in<br />

Butzbach can be seen in figure 1.<br />

Evacu<strong>at</strong>ed tube<br />

collectors<br />

60 m²<br />

aperture area<br />

<strong>Cooling</strong><br />

tower 1<br />

W<strong>at</strong>er<br />

<strong>Cooling</strong><br />

tower 2<br />

<strong>Cooling</strong><br />

shaft<br />

Gas<br />

boiler<br />

Cold w<strong>at</strong>er<br />

storage<br />

1000 l<br />

Airh<strong>and</strong>ling<br />

units<br />

Chilled<br />

ceilings<br />

Hot w<strong>at</strong>er<br />

storage<br />

3000 l<br />

Chiller 1<br />

10 kW<br />

Chiller 2<br />

10 kW<br />

<strong>He<strong>at</strong>ing</strong><br />

circuit<br />

Figure 1: Simplified scheme of the he<strong>at</strong>ing <strong>and</strong> cooling system in the low energy building of<br />

the Technical College Butzbach. Source: Fraunhofer ISE

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