This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studie...This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studied for continental climatic conditions. The district network study bases on 21 buildings located near to the Gulf of Finland. Industrial reversible heat pump technology is selected to cover heating and cooling loads for the new buildings. Combination of existing district heating and heat pump technology is considered for existing buildings. The results show possibilities, threats and need for further research of the sea water based heat pump district network implementation.展开更多
This paper describes the Danish legal framework for district cooling as an example of a model which so far has had limited success. A number of suggestions are analysed and discussed.
An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the t...An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable.展开更多
The paper presents a novel demand-responsive control strategy to be equipped centrally at the district level for district heating systems.The demand-responsive feature was maintained as to both the direct and the indi...The paper presents a novel demand-responsive control strategy to be equipped centrally at the district level for district heating systems.The demand-responsive feature was maintained as to both the direct and the indirect substation configurations(by basing on their rating measures)in order to achieve lowest possible return temper-ature degrees from the end-user substations.Different than the traditional weather-compensation based supply temperature resetting,the new control strategy was formulated to adjust the supply temperature at the district level as to the cooling performance at the end-user substations.Two different simulations were carried out in order to quantify the benefits of the novel control strategy as compared to the traditional weather-compensation,equipped both at the substation level and the district level.The results obtained showed that the new control strategy,when considering the electricity loss at the heat production plant,shows superiority when compared to other control strategies.展开更多
综合能源系统(integrated energy system,IES)是未来能源消费方式的重要发展方向,实现多区域IES的协同规划与调度对进一步提高其经济效益和环境效益至关重要,为此首要的问题是区域冷、热网的建模。文中基于传热学的基本原理建立了区域...综合能源系统(integrated energy system,IES)是未来能源消费方式的重要发展方向,实现多区域IES的协同规划与调度对进一步提高其经济效益和环境效益至关重要,为此首要的问题是区域冷、热网的建模。文中基于传热学的基本原理建立了区域热网能量传输通用模型,推导出热网热损方程,对其线性化得到热网能量流模型,同时推导了用于求解热网潮流(热媒流量、温度)的网络流量–温度基本方程。在冷热电联供系统运行优化模型基础上建立了含有热网的多区域IES优化混合整数线性规划模型。通过算例验证了模型的有效性。展开更多
文摘This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studied for continental climatic conditions. The district network study bases on 21 buildings located near to the Gulf of Finland. Industrial reversible heat pump technology is selected to cover heating and cooling loads for the new buildings. Combination of existing district heating and heat pump technology is considered for existing buildings. The results show possibilities, threats and need for further research of the sea water based heat pump district network implementation.
文摘This paper describes the Danish legal framework for district cooling as an example of a model which so far has had limited success. A number of suggestions are analysed and discussed.
基金supported by the National Natural Science Foundation of China(Grant No.51806062)Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51821004)the Fundamental Research Funds for the Central Universities(No.2020MS006).
文摘An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable.
基金supported by the‘European Union’,the‘Euro-pean Regional Development Fund(ERDF)’,‘Flanders Innovation&En-trepreneurship’and the‘Province of Limburg’.
文摘The paper presents a novel demand-responsive control strategy to be equipped centrally at the district level for district heating systems.The demand-responsive feature was maintained as to both the direct and the indirect substation configurations(by basing on their rating measures)in order to achieve lowest possible return temper-ature degrees from the end-user substations.Different than the traditional weather-compensation based supply temperature resetting,the new control strategy was formulated to adjust the supply temperature at the district level as to the cooling performance at the end-user substations.Two different simulations were carried out in order to quantify the benefits of the novel control strategy as compared to the traditional weather-compensation,equipped both at the substation level and the district level.The results obtained showed that the new control strategy,when considering the electricity loss at the heat production plant,shows superiority when compared to other control strategies.
文摘综合能源系统(integrated energy system,IES)是未来能源消费方式的重要发展方向,实现多区域IES的协同规划与调度对进一步提高其经济效益和环境效益至关重要,为此首要的问题是区域冷、热网的建模。文中基于传热学的基本原理建立了区域热网能量传输通用模型,推导出热网热损方程,对其线性化得到热网能量流模型,同时推导了用于求解热网潮流(热媒流量、温度)的网络流量–温度基本方程。在冷热电联供系统运行优化模型基础上建立了含有热网的多区域IES优化混合整数线性规划模型。通过算例验证了模型的有效性。
