Comprehensive analysis of the performance and intrinsic energy losses of centralized Domestic Hot Water (DHW) systems in commercial (educational) buildings

Kitzberger, Thomas; Kilian, David; Kotik, Jan; Pröll, Tobias

doi:10.1016/j.enbuild.2019.05.016

Cited by 19 publications

(8 citation statements)

References 19 publications

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“…The generator consumption Qin is calculated with an energetic balance in the stationary condition since the water heater's controller keeps the storage temperature constant. The same assumption was made in [55,56].…”

Section: Labeling Of Water Heatersmentioning

confidence: 93%

“…To calculate the fuel and electricity consumption of water heaters with storage, the thermal losses should be calculated defining the energetic model of the water heaters. The efficiency of the water heater is strongly dependent on the load [55][56][57][58][59][60][61]. One important indication is given in IEA-Task 45 [61] that reports the influence of technological evolution: storages built before 2005 have thermal losses 1.3 to 2 times higher than the new products.…”

Section: Labeling Of Water Heatersmentioning

confidence: 99%

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Labeling of Installed Heating Appliances in Residential Buildings: An Energy Labeling Methodology for Improving Consumers’ Awareness

Menegon

Lobosco²,

Micò

et al. 2021

Energies

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In the EU 28, the installed heating appliance stock is quite old, with an actual replacement rate of 4%. This is directly reflected in the average efficiency of the installed heating systems, where around 60% of the stock is rated with an energy class of C or D (the lowest classes of the energy label scale). The European project HARP aims at raising consumers’ awareness of the planned replacement of their old and inefficient heating appliances with more efficient and renewable solutions. In this direction, an energy labeling methodology for old appliances has been developed to rate the installed stock before the introduction of the EU energy label. The methodology has been developed for space heating appliances and water heaters, targeting two types of users: end consumers and professional users. The validation considered about 4600 space heating appliances and 800 water heaters built between 1972 and 2019. Three heating appliances and two water heaters were tested in the laboratory, confirming the reliability of the proposed methodology. The expected impact of defining an energy labeling methodology for installed heating appliances increases the current replacement rate of these appliances in the EU from 4% to 5%.

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Section: Labeling Of Water Heatersmentioning

confidence: 93%

Section: Labeling Of Water Heatersmentioning

confidence: 99%

Labeling of Installed Heating Appliances in Residential Buildings: An Energy Labeling Methodology for Improving Consumers’ Awareness

Menegon

Lobosco²,

Micò

et al. 2021

Energies

View full text Add to dashboard Cite

show abstract

“…Minimising DHW distribution and circulation losses improves the efficiency of the system and the energy performance of the whole building. Kitzberger et al [8] showed that minimising the runtime of the circulation pumps and decreasing hot water flow and storage capacities reduces the annual energy consumption for DHW by 15-25%. Mühlbacher and Carter [9] deduced a dependency between the energy loss and the operating time of the circulation pump in buildings with DHW circulation energy use from 21% to 65%.…”

Section: Introductionmentioning

confidence: 99%

Heat Loss Due to Domestic Hot Water Pipes

et al. 2021

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Domestic hot water (DHW) system energy losses are an important part of energy consumption in newly built or in reconstructed apartment buildings. To reach nZEB or low energy building targets (renovation cases) we should take these losses into account during the design phase. These losses depend on room and water temperature, insulation and length of pipes and water circulation strategy. The target of our study is to develop a method which can be used in the early stages of design in primary energy calculations. We are also interested in how much of these losses cannot be utilised as internal heat gain and how much heat loss depends on the level of energy performance of the building. We used detailed DHW system heat loss measurements and simulations from an nZEB apartment building and annual heat loss data from a total of 22 apartment buildings. Our study showed that EN 15316-3 standard equations for pipe length give more than a twice the pipe length in basements. We recommend that for pipe length calculation in basements, a calculation based on the building’s gross area should be used and for pipe length in vertical shafts, a building’s heating area-based calculation should be used. Our study also showed that up to 33% of pipe heat losses can be utilised as internal heat gain in energy renovated apartment buildings but in unheated basements this figure drops to 30% and in shafts rises to 40% for an average loss (thermal pipe insulation thickness 40 mm) of 10.8 W/m and 5.1 W/m. Unutilised delivered energy loss from DHW systems in smaller apartment buildings can be up to 12.1 kWh/(m2·a) and in bigger apartment buildings not less than 5.5 kWh/(m2·a) (40 mm thermal pipe insulation).

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“…One of their major findings was that collector orientation is the main factor causing construction limitation. Thomas Kitzberger [9] studied the losses in the centralized forced SWH for a commercial building. Due to its long piping, the system will run at low efficiency (2-12%) when the utilization rate is low.…”

Section: Introductionmentioning

confidence: 99%

Design Enhancement of Forced Circulation Solar Water Heater for Residential Buildings in Saudi Arabia

2021

JETP

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This study presents a proposed configuration of an innovative residential Solar Water Heater (SWH) system that will meet the hot water requirement and achieve a lower payback period in Saudi Arabia. Different SWH configurations were evaluated in terms of collector type, circulation method, heat exchanging mechanism and hot water storage. Also; the effect of SWH variable parameters on its thermal performance were determined. The variable parameters included collector tilt and orientation angles, albedo ratio, circulation flow rate, tank size, heat exchanger effectiveness and customer hot water supply temperature. The study covered five different cities, which represent different climate conditions. Proper optimization of SWH system configuration resulted in 30% reduction in the system payback period, which is about 4.3 years. Better economic figures can be expected for the installation of SWH systems in commercial and industrial sectors.

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Comprehensive analysis of the performance and intrinsic energy losses of centralized Domestic Hot Water (DHW) systems in commercial (educational) buildings

Cited by 19 publications

References 19 publications

Labeling of Installed Heating Appliances in Residential Buildings: An Energy Labeling Methodology for Improving Consumers’ Awareness

Labeling of Installed Heating Appliances in Residential Buildings: An Energy Labeling Methodology for Improving Consumers’ Awareness

Heat Loss Due to Domestic Hot Water Pipes

Design Enhancement of Forced Circulation Solar Water Heater for Residential Buildings in Saudi Arabia

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