planning:non-residential_passive_house_buildings:passive_house_retail

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planning:non-residential_passive_house_buildings:passive_house_retail [2018/04/23 15:08]
kdreimane [Thermal protection]
planning:non-residential_passive_house_buildings:passive_house_retail [2018/04/23 15:20] (current)
kdreimane [Thermal protection]
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 ==== Thermal protection ==== ==== Thermal protection ====
 +[{{ :picopen:01_pb40_einfuehrung_en_abb.4.png?250|**Figure 4: Display windows of existing buildings often still have single glazing.**}}]
  
 Like other efficiency measures, thermal protection has played a rather subordinate role in retail stores up till now (see e.g. Figure 4). Not only is it disregarded but sometimes it is even viewed critically: in buildings with sufficiently high internal heating loads, the issue arises whether a good level of thermal protection would be productive all at all, or whether it would be better to deliberately induce the maximum possible transmission losses in order to reduce the cooling demand. \\ Like other efficiency measures, thermal protection has played a rather subordinate role in retail stores up till now (see e.g. Figure 4). Not only is it disregarded but sometimes it is even viewed critically: in buildings with sufficiently high internal heating loads, the issue arises whether a good level of thermal protection would be productive all at all, or whether it would be better to deliberately induce the maximum possible transmission losses in order to reduce the cooling demand. \\
      
 In actual fact, further improvement of the thermal protection is pointless and will lead to an increased cooling demand, at the latest when the internal heat gains meet the maximum heating demand (Figure 5). \\ In actual fact, further improvement of the thermal protection is pointless and will lead to an increased cooling demand, at the latest when the internal heat gains meet the maximum heating demand (Figure 5). \\
-\\ + 
-|{{:picopen:01_pb40_einfuehrung_en_abb.4.png?400}}|\\ +[{{:picopen:01_pb40_einfuehrung_en_abb.5.png?450|**Figure 5: Useful energy demand of a supermarket (similar to Figure 1) for heating and cooling with different internal heat sources.** 
-|//**Figure 4: \\ Display windows of existing buildings \\ often still have single glazing.**//|\\ +An x-axis value of 0 shows the level of insulation required according to the German EnEV standard. The cooling demand is greater with higher internal loads, more insulation will then be contraproductive. Figure 7 demonstrates that additional natural ventilation in summer can solve this problem.}}] 
-\\ +
-|{{:picopen:01_pb40_einfuehrung_en_abb.5.png?500}}|\\ +
-|//**Figure 5: \\ Useful energy demand of a supermarket (similar to Figure 1) for heating \\ and cooling with different internal heat sources.** \\ \\ An x-axis value of 0 shows the level of insulation required according to the \\ German EnEV standard. The cooling demand is greater with higher internal loads, \\ more insulation will then be contraproductive. Figure 7 demonstrates that additional \\ natural ventilation in summer can solve this problem.//|\\ +
-\\+
 Since internal heat gains are a decisive influencing parameter for the concept of the structural envelope, these will be examined in more detail here. Figure 6 illustrates how great the fluctuations in the heat gains can be in retail stores. \\ Since internal heat gains are a decisive influencing parameter for the concept of the structural envelope, these will be examined in more detail here. Figure 6 illustrates how great the fluctuations in the heat gains can be in retail stores. \\
  
 Four full-range retail store variants are shown on the left. The variant "old" shows a market with inefficient lighting (installed output ca. 25 W/m²) and other equipment resulting in average heat dissipation of more than 20 W/m² into the room. On the other hand, an average of 50 W/m² of heat is withdrawn from the room by the open refrigerated shelves with poor air curtains and without roll-down night covers, so that there are net internal heat losses of more than 30 W/m² in the end. The total electricity consumption amounts to 640 kWh/(m²a). Additional air conditioning in summer is not required, instead the store has to be heated almost all year round to compensate for the heat that is withdrawn. \\ Four full-range retail store variants are shown on the left. The variant "old" shows a market with inefficient lighting (installed output ca. 25 W/m²) and other equipment resulting in average heat dissipation of more than 20 W/m² into the room. On the other hand, an average of 50 W/m² of heat is withdrawn from the room by the open refrigerated shelves with poor air curtains and without roll-down night covers, so that there are net internal heat losses of more than 30 W/m² in the end. The total electricity consumption amounts to 640 kWh/(m²a). Additional air conditioning in summer is not required, instead the store has to be heated almost all year round to compensate for the heat that is withdrawn. \\
-\\ +
-|{{:picopen:01_pb40_einfuehrung_en_abb.6.png?500}}|\\ +
-|**//Figure 6: \\ Variation range of the internal heat gains. \\ TK = deep freezing, NK = Normal cooling//**|\\ +
-\\+
 With the standard equipment commonly used nowadays, consisting of roll-down night covers in front of the refrigerated shelves and lighting using T8 lamps with an installed output of 10 W/m², the electricity consumption is just 260 kWh/(m²a), and heat withdrawal is already significantly less. Heat flows can be controlled even more easily if the best technology available today is used with moderate levels of illuminance, in accordance with the "good" scenario. For the "future" variant, one would expect optimised refrigeration equipment and reduced electricity consumption for lighting, even if the levels of illuminance are increased. If the efficiency of the bakery section and other electrical applications is also improved at the same time, then the internal gains will amount to just a few watts per square metre. Depending on the level of illuminance and the proportion of refrigeration equipment, this may be positive or negative. \\ With the standard equipment commonly used nowadays, consisting of roll-down night covers in front of the refrigerated shelves and lighting using T8 lamps with an installed output of 10 W/m², the electricity consumption is just 260 kWh/(m²a), and heat withdrawal is already significantly less. Heat flows can be controlled even more easily if the best technology available today is used with moderate levels of illuminance, in accordance with the "good" scenario. For the "future" variant, one would expect optimised refrigeration equipment and reduced electricity consumption for lighting, even if the levels of illuminance are increased. If the efficiency of the bakery section and other electrical applications is also improved at the same time, then the internal gains will amount to just a few watts per square metre. Depending on the level of illuminance and the proportion of refrigeration equipment, this may be positive or negative. \\
  
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 If no frozen foods are being sold, then internal gains can even be more than 20 W/m² with high illuminance levels. At some point it will become necessary to use a high-performance air conditioning system with corresponding energy consumption in order to equalise the night/day fluctuations. \\ If no frozen foods are being sold, then internal gains can even be more than 20 W/m² with high illuminance levels. At some point it will become necessary to use a high-performance air conditioning system with corresponding energy consumption in order to equalise the night/day fluctuations. \\
  
-[{{ :picopen:01_pb40_einfuehrung_en_abb.7.png?400|**Figure 7: As in Figure 5, but with an additional air change rate of 3 h<sup>-1</sup> for space cooling.**}}]+[{{:picopen:01_pb40_einfuehrung_en_abb.6.png?500|**Figure 6: Variation range of the internal heat gains. TK = deep freezing, NK = Normal cooling**}}] 
 + 
 +[{{:picopen:01_pb40_einfuehrung_en_abb.7.png?550|**Figure 7: As in Figure 5, but with an additional air change rate of 3 h<sup>-1</sup> for space cooling.**}}] 
 + 
 +----
  
 There are two aspects which need to be kept in mind with regard to the question of the appropriate level of thermal protection: the planned use of the building can change several times during the lifetime of the building envelope; adjustment of the sales concepts should at least be expected; the envelope should still continue to function. Significant improvements are expected in the next few years, particularly with reference to the efficiency of lighting (see the article "Daylight and artificial lighting" by Wilfried Pohl in the [[http://passiv.de/literaturbestellung/index.php/en/product/view/31/268|Protocol Volume No. 40]] of the "Research Group for Cost-effective Passive Houses"; //only available in German//). In addition, goods can be presented appropriately by means of well thought-out concepts for lighting, even with moderate illuminance levels. \\ There are two aspects which need to be kept in mind with regard to the question of the appropriate level of thermal protection: the planned use of the building can change several times during the lifetime of the building envelope; adjustment of the sales concepts should at least be expected; the envelope should still continue to function. Significant improvements are expected in the next few years, particularly with reference to the efficiency of lighting (see the article "Daylight and artificial lighting" by Wilfried Pohl in the [[http://passiv.de/literaturbestellung/index.php/en/product/view/31/268|Protocol Volume No. 40]] of the "Research Group for Cost-effective Passive Houses"; //only available in German//). In addition, goods can be presented appropriately by means of well thought-out concepts for lighting, even with moderate illuminance levels. \\
planning/non-residential_passive_house_buildings/passive_house_retail.1524488919.txt.gz · Last modified: 2018/04/23 15:08 by kdreimane