Heat Loss Due to Domestic Hot Water Pipes

Anti Hamburg, Alo Mikola, Tuule-Mall Parts and Targo Kalamees
Additional contact information
Anti Hamburg: nZEB Research Group, Tallinn University of Technology, 19086 Tallinn, Estonia
Alo Mikola: nZEB Research Group, Tallinn University of Technology, 19086 Tallinn, Estonia
Tuule-Mall Parts: nZEB Research Group, Tallinn University of Technology, 19086 Tallinn, Estonia
Targo Kalamees: nZEB Research Group, Tallinn University of Technology, 19086 Tallinn, Estonia

Energies, 2021, vol. 14, issue 20, 1-19

Abstract: 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/(m 2 ·a) and in bigger apartment buildings not less than 5.5 kWh/(m 2 ·a) (40 mm thermal pipe insulation).

Keywords: DHW heat loss; DHW circulation; energy performance (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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