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Low-temperature residual heat and heat potentials of renewables below 70°C often stay unused as either the distance between source and demand is too large or the heat does not occur at demand times. Hybrid thermo-chemical networks have a high potential to improve this situation, to transport thermal energy potential over long distances and to bridge short to medium time differences between demand and supply. The storage and transport potential of thermo-chemical substances has been identified and examined comprehensively. However, none of the studies addressed the replacement of water by thermo-chemical fluids (TCF) in district networks. Therefore this paper elaborates the use of TCF in such networks. First, it elaborates technological application cases showing the theoretical potential to reduce primary energy consumption up to 85%. Second, it presents technological components that have been developed for thermo-chemical systems.

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“…This is calculated based on the relative humidity and saturation mass xsat dependent on the temperature θ in °C according to [44] …”

Section: Exploiting Low-temperature Residual Heat For Tcf Recoverymentioning

confidence: 99%

Hybrid thermo-chemical district networks – Principles and technology

Geyer

Buchholz

et al. 2017

Applied Energy

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“…5 In this way, PCMs store energy in the transition from solid to liquid and vice versa and thus are able to store high amounts of energy at a desired temperature, which is the melting temperature of the corresponding material. 6 Most people feel comfortable at a temperature between 19 C and 23 C and a humidity of 40%-60%, 7 making the 21 C material highly promising for room conditioning. Many attempts have already been made to use PCMs in building applications.…”

Section: Introductionmentioning

confidence: 99%

Passive room conditioning using phase change materials—Demonstration of a long‐term real size experiment

et al. 2020

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Summary The thermal properties of lightweight buildings can be efficiently improved by using phase change materials (PCMs). The heat storage capacity of the building can be extended exactly at the desired temperature level, which leads to an enormous increase in residential comfort. This is shown in the present paper using the example of a prefabricated wooden house. The house was divided into two identical rooms. One of them was equipped with almost one ton of phase change material based on salt hydrates with a melting temperature of approx. 21°C. The material was encapsulated in 1‐l Polyethylene containers and installed in two back‐ventilated layers inside of the walls. The house was monitored for a period of 87 days in terms of temperatures, solar radiation and air velocity inside the PCM wall system. A considerable temperature buffering could be observed in the PCM room compared to the reference room. An overall reduction of the temperature fluctuations of 57% and a reduction of the day/night fluctuations of 62% compared to the reference room could be obtained. In addition, a prediction regarding the energy demand of such buildings is discussed on the basis of a simulation program. Thus, the annual cooling capacity can be reduced by 36.5% compared to the regular timber construction technique by introducing PCM. Furthermore, the good correlation of the simulation results with the experimental ones allows using the simulation as a tool to design a house with additional thermal storages.

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