Development of a dynamic analytical model for estimating waste heat from domestic hot water systems

How to get your feet wet: Integrating urban water and building engineering for low-energy domestic hot water systems

“…Cholewa et al, [21] estimate heat losses to range from 20 % of the DHW energy loads for typical single family homes (SFH) to 70 % for multi-apartment buildings with a circulation system. Recently, Marini et al, [22] have estimated heat losses from dwellings in the UK between 4 % of the DHW energy loads -for a combi-boiler system -and 31 % -for a regular boiler with storage tank -, showing that short tap draw-offs were responsible for most of the wasted heat. Our own modeling efforts [23] confirm this mechanism.…”

Optimisation of a smart energy hub with integration of combined heat and power, demand side response and energy storage

“…Hourly time step is used in the optimisation model, thus the constraint in (6) restricts how much the power production of a CHP unit may increase or decrease between two consecutive hours. In this model, the heat transmission loss is incorporated into the cost model as a constant percentage of the heat energy transmitted, which is often used in large systems [34,35], and the loss percentage can be estimated from the design data of large heat pipes. Indeed, the modelling for the heat loss of the pipes from CHP to end users can be found from [35] and is briefly summarized as follows.…”

“…where 𝑚̇ is the flow rate, 𝑐 𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 is the water specific heat, 𝑇 𝑖𝑛,𝑤𝑎𝑡𝑒𝑟 and 𝑇 𝑜𝑢𝑡,𝑤𝑎𝑡𝑒𝑟 are the inlet and outlet water temperatures, 𝐴 𝑙 is the loss coefficient, and ∆𝑇 = (𝑇 𝑖𝑛,𝑤𝑎𝑡𝑒𝑟 − 𝑇 𝑜𝑢𝑡,𝑤𝑎𝑡𝑒𝑟 )/ln ((𝑇 𝑖𝑛,𝑤𝑎𝑡𝑒𝑟 − 𝑇 𝑎 )/(𝑇 𝑜𝑢𝑡,𝑤𝑎𝑡𝑒𝑟 − 𝑇 𝑎 )) with 𝑇 𝑎 the ambient temperature. When the water flow is static, a similar model can be found from [35]. The above heat loss models are simplified by using the heat loss coefficient in this work.…”

CHP systems optimal allocation in the interconnected heat and electricity distribution network based on minimizing electrical and heat transfer losses

“…Several studies have been conducted in the field of modeling the HTL through pipelines. In [35], an analytical dynamic model has been developed to estimate heat loss from a domestic hot water system. Chicherin et al [36] evaluated heat loss of district heating networks using various states of insulation, detailed information on thermal conductivity, internal heat transfer coefficient, and geometry of the concrete trench.…”

“…Several studies have been conducted in the field of modeling the HTL through pipelines. In [35], an analytical dynamic model has been developed to estimate heat loss from a domestic hot water system. Chicherin et al .…”