• Energy Research

Space cooling demand is increasing globally due to climate change. Cooling has also been linked to all 17 sustainable development goals of the United Nations. Adequate cooling improves productivity and thermal comfort and can also prevent health risks. Meanwhile, policy initiatives such as the European Union’s Green Deal require participants to cut greenhouse gas emissions and reduce energy use. Therefore, novel cooling systems that are capable of efficiently producing high levels of thermal comfort are needed. Radiant cooling systems provide a design capable of fulfilling these goals, but their application in hot and humid climates is limited due to the risk of condensation. In this study, we compare the performances of radiant cooling systems with and without dehumidification. The studied systems are supplied by geothermal energy. The study is conducted using building energy models of a small office building belonging to a three-building school complex located in Sant Cugat near Barcelona in Spain. The studied location has a Mediterranean climate. The simulations are conducted using IDA Indoor Climate and Energy 4.8 simulation software. The results show that the radiant cooling system with dehumidification (RCD) produces considerably improved thermal comfort conditions, with maximum predicted mean vote (PMV) reached during the cooling season being 0.4 (neutral) and the maximum PMV reached by the radiant cooling system without dehumidification (RC) being 1.2 (slightly warm). However, the improved thermal comfort comes at the cost of reduced energy and exergy efficiency. The RCD system uses 2.2 times as much energy and 5.3 times as much exergy as the RC system. A sensitivity analysis is also conducted to assess the influence of selected input parameters on the simulation output. The results suggest that maximising dehumidification temperature and minimising ventilation flow rate can improve the energy and exergy efficiency of the RCD system while having a minor effect on thermal comfort.

Minimizing thermal losses through windows and maintaining large glazing areas to provide adequate natural lighting in residential buildings are essential considerations for modern architecture, sus ...

Low-temperature heating (LTH) has shown promising advantages and shortcuts to improve the thermal performance of radiators. An investigation on which renovation measures from the demand side, can c ...

AbstractEnergy requirements for space heating and domestic hot water supplies in the Swedish building sector are responsible for almost 60% of the total energy used. To decrease this enormous figure, energy saving measures are required, as well as opportunities to use low-temperature heating systems for increase sustainability. The present paper studies low-temperature heating systems, including heat production units (district heating or heat pumps) and heat emitting units in the room. The aim was to find an answer to the question of whether or not low-temperature heating systems are energy efficient and sustainable compared with conventional heating systems. To answer this question, we considered different efficiency aspects related to energy and exergy. The analysis showed that low-temperature heating systems are more energy efficient and environmentally friendly than conventional heating systems. This was attributed to heat pumps and district heating systems with lower temperature heat emitters using a greater share of renewable resources and less auxiliary fuels. This report discusses the pros and cons of different types of low-temperature heat emitters.

Sweden is actively engaged in accelerating the sustainable transformation of existing building and energy systems. Most traditional investigations of this subject have been based on final energy sa ...

Abstract The main focus of the present study was to find design requirements for an air-heater that would be able to operate at low pressure loss and low-temperature water supply. The idea was to combine this low-temperature air-heater with existing radiator systems so that they can operate at similar low-temperature supply as used in floor heating systems. Results indicated that the proposed air-heater was able to lift the temperature of supply air at 10 l/s from −15 °C to 18.7 °C using 40 °C water supply. In addition, a thermal performance analysis showed that radiator systems equipped with the proposed air-heater could meet a space heat loss of 35.6 W per square meter floor area, using supply water of 40 °C. It was also shown that the heat pump efficiency in the hydronic system with proposed air-heater was 8–18% higher than in system without air-heater. All results in the present study were obtained by analytical (semi-empirical) and numerical (Computational Fluid Dynamics – CFD) calculations.

Radiant cooling systems are a subject of increasing scientific interest due to their efficiency and ability to use high-temperature cooling sources. In hot and humid conditions, they have generally been studied in combination with dehumidification systems. For retrofit projects, a control system that would eliminate the need for dehumidification would be beneficial. In the present study, a passive geothermal-based radiant high-temperature cooling system is studied in a Mediterranean climate. The system is operated with supply water temperature control using dew point temperature as a controlling variable. The system's performance is compared with that of an all-air cooling system. The systems are evaluated using IDA-ICE building energy simulations, validated with on-site measurement data. The results show that the radiant cooling system produces the same level of thermal comfort with 40% lower energy use and 85% lower exergy consumption than the all-air system. The risk of condensation limits the cooling capacity of the radiant cooling system. Consequently, insufficient cooling capacity causes thermal discomfort for the occupants due to the operative temperature exceeding 26 °C. Datasets: "Building energy simulation data results" and "Acquired data from existing and/or new installed meters or from existing BEMS (pre intervention EcoSCADA monitoring data)" - Raw data is available upon request. Follow the link and fill the request form.

Energy consumption, thermal environment and environmental impacts were analytically and experimentally studied for different types of heat emitters. The heat emitters studied were conventional radi ...