Dynamic response of gravity-driven flow in multi-section absorption heat pump

Metamorphoses of cogeneration-based district heating in Romania: A case study

Absorption heat pumps can lift a lower temperature waste heat source to a higher temperature useful output. In that process, it uses less electricity as an input compared to heat pumps with electrical compressors. Therefore, in some cases, it can be used to lift a lower temperature waste heat source to a higher temperature useful output with less electricity consumption. Absorption heat pumps are not very widely spread in district heating, mostly because there aren’t many suitable waste heat sources or conditions needed to run them. Tallinn has a district heating system with an annual generation of more than 2 TWh and a goal to make it an entirely carbon neutral district heating system by 2030. Tallinn has also started to develop a district cooling network, and by the end of 2023, the installed capacity was about 6 MW. District cooling capacity is estimated to grow to around 100 MW in 2030. This paper investigates different types of absorption heat pumps and the possibilities of integrating an absorption heat pump to a district cooling plant with the purpose of using waste heat from the cooling plant for renewable heat generation, that can be used in district heating. Different technical aspects are examined to find a suitable production solution, are presented as results. From an economical point of view, the cost of heat to cover peaks with an absorption heat pump is calculated. The effect of reducing fossil fuel use in the Tallinn district heating network with an absorption heat pump is estimated.

Techno-economic model for district heating systems

Comparative Analysis Between District Heating and Geothermal Heat Pump System

Promoting efficient district heating in Estonia

District heating systems (DHSs) which utilize excess heat play an important role in energy infrastructure in many European countries. In contrast to Europe, the DHS is not common and excess heat is not reused effectively in Japan. Almost all the DHSs in Japan were designed as first-generation district heating (1GDH) systems or 2GDH systems. No 4GDH systems have been introduced in Japan. The present study designs a 4GDH system utilizing excess heat from a wide area of Northern Japan and evaluates its feasibility. First, available heat amounts from two excess heat resources were calculated: waste incineration plants and thermal power plants. Second, heat demand from both residential and commercial sectors was estimated using a 1 km mesh, and a heat load curve was created for each mesh based on load curve data. Third, the DHS was designed with excess heat plants as a supply-side heat resource, and spatial information of the demand side made use of the geographical information system (GIS). Further analysis was conducted on selected DHSs in three cities in order to evaluate those systems’ feasibility based on energy efficiency, CO2 emissions, and economic aspects. The result shows that 70.5 PJ of heat can be supplied by DHS in Northern Japan, replacing imported fossil fuels such as petroleum and LPG with regional excess heat. The designed DHS could supply heat with equivalent costs compared to European countries.

Machine-learning-based multi-step heat demand forecasting in a district heating system

Double-section absorption heat pump for the deep recovery of low-grade waste heat

A new waste heat district heating system with combined heat and power (CHP) based on ejector heat exchangers and absorption heat pumps

The Imanta district heating plant began operation in 1974 as one of the main heating plants for the Riga district heating system. Until now, it has undergone several reconstructions. First, the ordinary boiler plant with steam and hot water boilers was reconstructed to be a natural gas-fueled combined cycle cogeneration plant supported with hot water boilers. Then, one of the cooling towers of the cogeneration section was replaced by an absorption heat pump/chiller, thus providing the closed cooling water circulation system and recovering 2 MWth (7 MMBTU/h) low-grade heat otherwise lost in the atmosphere. The driving force for the absorption heat pump is steam produced by the steam boiler (3 MWth = 10 MMBTU/h) already located at the boiler plant. The efficiency of the absorption heat pump is closely related to the operation of the cogeneration unit, outside temperature, and district heating water temperature regimes. The case study confirms that a more efficient energy production system reduces the fuel consumption with the same amount of the produced energy, thus lowering the expenses on energy production and reducing the amount of the polluting emissions into the atmosphere.

Accounting for external environmental costs in a study of a Swedish district-heating system – an assessment of simplified approaches

Collaborative scheduling and flexibility assessment of integrated electricity and district heating systems utilizing thermal inertia of district heating network and aggregated buildings

Effects of the operation regulation modes of district heating system on an integrated heat and power dispatch system for wind power integration

In order to decrease the energy consumption of large-scale district heating systems with cogeneration, a district heating system is presented in this paper based on absorption heat exchange in the cogeneration system named Co-ah cycle, which means that the cogeneration system is based on absorption heat exchange. In substations of the heating system, the temperature of return water of primary heat network is reduced to about 25°C through the absorption heat-exchange units. In the thermal station of the cogeneration plant, return water is heated orderly by the exhaust steam in the condenser, the absorption heat pumps, and the peak load heater. Compared with traditional heating systems, this system runs with a greater circuit temperature drop so that the delivery capacity of the heat network increases dramatically. Moreover, by recovering the exhausted heat from the condensers, the capacity of the district heating system and the energy efficiency of the combined heat and power system (CHP system) are highly developed. Therefore, high energy and economic efficiency can be obtained.

District heating and cooling (DHC) systems play an important role under the new European Union (EU) energy transition strategy. Thermal energy networks are helping to stimulate the development of alternative technologies based on a broad range of renewable energy sources. The present study analysed the current situation of DHC systems in Spain and provides an overview of the challenges and future opportunities that their use will entail. Its objective is to assess thermal energy conversion and management from a holistic perspective, including a study of existing energy infrastructures. The focus of this study lies on Spain given the country’s abundance of natural resources such as renewable energy sources including solar energy, biomass and geothermal energy, among others, as well as its strategic location on the map of the EU. Based on the analysis of the three factors for energy conversion in a district heating system, namely resources, technology, and management, the methodology provided an assessment of the different factors involved in running a DHC system. The results show an estimated total production for DHC networks of 1448 MWth, of which 72% is supplied purely by renewable energy sources.