In the area of thermal management, thermal control elements (TCEs) and thermal control circuits (TCCs) are proving to be innovative solutions to the challenges of temperature control and heat dissipation in various applications, ranging from electronic cooling to energy conversion and temperature control in buildings. Their integration promises to improve power density, energy efficiency, system reliability and system life expectancy. With the aim of connecting researchers in the field of thermal management and accelerating the development of TCEs and TCCs, we have developed an open-source TCC simulation tool called TCCbuilder that enables a quick and easy time-dependent 1D numerical analysis of the behavior of TCEs and TCCs. It uses the heat conduction equation to solve temperature profiles in different devices. The TCCbuilder application offers features not previously available with any other TCC modeling tool: a large adjacent library of materials and TCEs as well as a user-friendly graphical user interface (GUI).

Heating and cooling systems account for approximately 50% of global energy consumption and contribute 40% of carbon dioxide emissions. District-heating systems offer enhanced energy efficiency, diversification, independence from energy sources, and the utilization of waste and renewable energy sources. One key energy-efficiency measure in district heating is reducing the supply and return temperatures. Fourth-generation district-heating systems operate with supply temperatures of 50 to 60 °C, enabling better utilization of renewable and waste heat. Fifth-generation district-heating systems further lower the supply/return temperatures, requiring additional heat sources, such as boosters, to heat domestic hot water. Heat pumps, specifically vapor-compression heat pumps, are the most energy-efficient devices for converting fuels or electricity into heat for space and water heating. However, vapor-compression technology faces challenges related to environmentally friendly refrigerants, noise, vibration, compactness, and energy efficiency, especially for small units. In this study, we introduce a novel design of thermoelectric-based heat-pump booster. Despite its lower exergy efficiency, this technology offers advantages such as compactness, silent operation without vibration, easy power control, and longevity. We demonstrate that these thermoelectric heat-pump boosters can increase the supply-water temperature of district-heating systems from around 32 °C to 42 °C, with a heating coefficient of performance equal to 2.4 and an exergy efficiency of 9.9 %.

The quest for better performance from magnetocaloric devices has led to the development of thermal control devices, such as thermal switches, thermal diodes, and thermal capacitors. These devices are capable of controlling the intensity and direction of the heat flowing between the magnetocaloric material and the heat source or heat sink, and therefore have the potential to simultaneously improve the power density and energy efficiency of magnetocaloric systems. We have developed a new type of thermal control device, i.e., a silicon mechanical thermal switch capacitor ( TSC). In this paper we first review recently developed thermal switches based on micro-electromechanical systems and present the operation and structure of our new TSC. Then, the results of the parametric experimental study on the thermal contact resistance, as one of the most important parameters affecting the thermal performance of the device, are presented. These experimental data were later used in a numerical model for a magnetocaloric device with a thermal switch-capacitor. The results of the study show that for a single embodiment, a maximum cooling power density of 970 W m ^−2 (510 W kg _mcm ^−1 ) could be achieved for a zero-temperature span and an operating frequency of 5 Hz. However, a larger temperature span could be achieved by cascading multiple magnetocaloric elements with TSCs. We have shown that the compact TSC can be used in caloric devices, even with small temperature variations, and can be used in a variety of practical applications requiring thermal regulation.