The facade design shown in Figure 1 was numerically investigated. The results obtained for two climatic conditions, Barcelona and Geneve, are shown in Figure 4.

Figure 4: Monthly performance of the facade for domestic hot water production: solar fraction and solar efficiency. Consumption profile 1, (with noon draw), tank stratification considered as given by 5 nodes.

It is observed that solar fraction is less variable in Barcelona climate, while it suffers depreciations in Geneve climate in the winter months. Solar Efficiency presents for both climates a similar performance. For April month, for instance, 32% of total domestic hot water load may be satisfied by the solar facade if it is located in Geneve. For a Barcelona location, facade provides 40% of total load. Regarding Solar Efficiency, the variation is lower, 46% for Geneve and 49% for Barcelona. Annual values are shown in Table 4, where OTL stands for the mean annual outlet temperature from water tank.

The influence of the consumption profile has been analyzed for a design addressed to Barcelona climate. Monthly solar fraction and solar efficiency are shown in Figure 5 for the two profiles described in Tables 1 and 2. Consumption profile 1 (with noon draw), presents better results all around the year. The differences are more noticeable in the central months (June, July and August). In the rest of the year, differences are negligible.

The influence of stratification within the tank has been analyzed conside­ring two possible le­vels. Stratification represented by 5 and 10 nodes. Di­fferences obtained are negligible, al­though it is pos­sible to get larger useful energy with

a higher level of Figure 5: Monthly performance of the facade for domestic hot water stratification in wa- production: solar fraction and solar efficiency. Two consumption pro — ter tank Data are files (1: morning, noon and evening, 2: morning and evening). Data corresponding to Barcelona

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