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The heat pump operated single-stage humidification-dehumidification desalination system, configured with a subcooler and a heat regenerator, has been proven highly effective in improving both freshwater productivity and energy efficiency. To investigate the potential benefits of increasing the number of humidification stages, this paper presents a heat pump operated two-stage humidification-dehumidification desalination system by adding a pre-humidifier. Subcooler and condenser of the heat pump are used as the heat sources of the main humidifier and the pre-humidifier, respectively. Through parametric studies, a comparative analysis is conducted on the thermodynamic and economic performances of both the heat pump operated single-stage system and two-stage system at various operating conditions. The results show that such system modification can greatly improve system performances. Compared to the single-stage system, the maximum freshwater productivity of the two-stage system is 42.89 kg/h, increased by 19.77 %; the peak gain output ratio is 7.93, up by 9.53 %; and the lowest specific electricity consumption is 79.34 kWh/m3, reduced by 15.15 %. Furthermore, the freshwater production cost for the two-stage system, ranging from 7.78 to 13.33 $/m3, is also superior that of the single-stage system, further demonstrating its substantial value in practical product development and market promotion. • A heat pump operated two-stage humidification-dehumidification system is proposed. • Performances of single and two-stage systems are compared at identical conditions. • Freshwater production costs of the two-stage system range from 7.78 to 13.33 $/m3. • The two-stage system is significantly more efficient than the single-stage system. [ABSTRACT FROM AUTHOR]

Industrial steam heating is a significant aspect of energy consumption in China, playing a crucial role in industrial energy efficiency. Historically, demand response research has predominantly focused on the electricity sector, with limited emphasis on steam supply. This study explores a novel Time-of-Use pricing approach for steam heating systems, anchored in the demand response theory of price incentives. It develops a peak-valley segmentation method by considering both the load differences between supply and demand and the thermal storage capacity of the pipeline system. Additionally, the paper delves into user response characteristics to formulate an optimized Time-of-Use pricing model for steam heating systems. Implemented in a Jiangsu-based case study, the model demonstrates significant efficiency improvements: it reduces the peak-valley load difference by up to 68.3% and cuts steam purchasing costs by ¥135,000. Furthermore, the alignment between the users' total steam load curve and the heat source's steam supply is enhanced by 18.8%, illustrating the model's effectiveness in balancing demand and supply. • Cluster analysis to extract steam user load characteristics. • Divide peak/valley times based on network storage and user traits. • Create a multi-objective Time-of-Use model for steam pricing optimization. • Carry out a case validation in an actual industrial park in Jiangsu. [ABSTRACT FROM AUTHOR]

In this paper, TRNSYS is used to simulate the heating systems of air-cooling concentrating photovoltaic/thermal (CPVT) coupled air source heat pump and water-cooling CPVT coupled air source heat pump. Besides, Grasshopper is adopted for multi-objective optimization of air-cooling system. This study not only proposed two hybrid systems and enriched the research of CPVT coupled air source heat pump, but also proposed a multi-objective optimization method, which uses Grasshopper to invoke TRNSYS. Compared with the air source heat pump system, the annual average COP of heat pump in the air-cooling system increases by 22.8%, and that of the water-cooling system decreases by 6%. The primary energy saving rate of the air-cooling system is 1.06 times and 6.67 times that of the water-cooling system and the air source heat pump system. The optimized air-cooling system reduces the annual total cost by 2.83%, and increases the energy utilization coefficient by 4.76%. The proposed air-cooling system has obvious advantages in energy saving and improving COP of heat pump. This study is useful for the cost savings and energy conservation of air-cooling concentrating photovoltaic/thermal (CPVT) coupled air source heat pump systems based on urban public buildings. • Models of different CPVT coupled ASHP systems are established in TRNSYS. • The optimization method integrates the advantages of TRNSYS simulation and the advantages of GH parameterization. • The systems are analyzed and compared from energy utilization coefficient, exergy efficiency, primary energy saving rate, annual total cost and net present value. • The ACPVT-ASHP system performance is best when the ASHP capacity is 9.9 kW and the length of PV cells is 1.819 m. [ABSTRACT FROM AUTHOR]

The problem addressed in this work is the enhancement of energy efficiency in buildings, primarily focused on heating control. The paper highlights the importance of addressing this challenge, given that HVAC systems are responsible for over 60% of total energy consumption in buildings, making them the largest energy consumers in both the residential and nonresidential sectors. This paper presents a methodology for developing a model predictive control (MPC) system based on artificial neural network (ANN) models, with the aim of improving the energy efficiency of buildings. This approach involves the creation of a training dataset using dynamic thermal simulation tools, enabling the learning of the ANN model that is responsible for predicting future states within an MPC optimization loop. Additionally, the implementation leverages advanced technologies such as Field-Programmable Gate Arrays (FPGAs), specifically the PYNQ board, Wi-Fi modules, and MQTT communication to enhance scalability, deployment, and adaptability. The study evaluates the proposed Neural Network Model Predictive Control (NNMPC) strategy implemented on the PYNQ, reporting a substantial reduction of 38.53% in heating energy consumption in buildings compared to a basic On/Off control approach for 24-hour simulation. This outcome underscores the solutions significant potential for energy savings in building heating systems. [ABSTRACT FROM AUTHOR]

Adsorption carbon capture has shown its superiority in energy consumption and cost investment when compared with common amine scrubbing technologies. However, high regeneration energy demand of adsorbents is still a challenge for large-scale application. This paper proposes a temperature vacuum swing adsorption system integrated with auxiliary heating and cooling technology. Absorption chiller and double-stage absorption heat transformer (DAHT) are introduced from the perspective of adsorption and desorption process of CO 2 capture system. Results indicate that when the duration of each step increases from 25 min to 45 min, the CO 2 recovery rate decreases from almost 100 %–75.7 %, and CO 2 purity increases slightly from 89.6 % to 91.1 %. Considering the temperature grade of waste heat, heat consumption of the absorption chiller assisted system is lower than that of DAHT for original and adjusted cases at a generation temperature of 58 °C. If the desorption temperature decreases from 120 °C to 100 °C, heat consumption of the absorption chiller decreases from 1.90 GJ·ton−1 to 1.76 GJ·ton−1, but the average capture capacity decreases from 306.3 ton·ton−1 ad to 272.1 ton·ton−1 ad. It is demonstrated that both absorption chiller and absorption heat transformer could be promising solutions to reducing the energy consumption of CO 2 capture system. Absorption chiller has a priority over DAHT in regions with low temperature heat sources. Moreover, a tradeoff between adsorbent loss and heat consumption should be found when choosing the appropriate heat pump for practical application. [Display omitted] • Adsorption carbon capture integrated with absorption chiller is initially proposed. • Absorption chiller is beneficial for reduction of heat consumption of capture. • Decrease of desorption temperature has great influence on system performance. • Heat pump assisted adsorption capture is a promising way for energy saving. [ABSTRACT FROM AUTHOR]

50–80 °C heat sources are abundant in renewable energy areas and industrial processes. However, they are difficult to be effectively used due to their ultralow grade. In order to solve this problem, this paper presents a high-efficient hybrid adsorption refrigeration system combing with desiccant coated heat exchangers. In this study, the performance of the hybrid system is experimentally investigated and parametric effects are fully discussed. Results indicate that the hybrid system operates efficiently across a wide heat source range of 50–80 °C. A high-temperature hot water facilitates the cooling production of the hybrid system, while a low-temperature hot water is more beneficial to the COP promotion. Also, a lower cooling water temperature, higher air temperature, higher relative humidity and longer switch time can enhance system performance. The optimal cooling capacity is quantified as 4579 W when powered by 80 °C hot water and the COP reaches its maximum of 0.673 under a heat source temperature of 50 °C. Comparison results show that compared with present systems, the hybrid system has greater adaptability as well as higher efficiency in utilizing 50–80 °C ultralow-grade heat sources, and can satisfy the simultaneous demand for cooling and dehumidification, which offers a promising way to high-efficient energy utilization and sustainable development. • A hybrid adsorption system using desiccant coated heat exchangers is presented. • The hybrid system operates efficiently across a wide heat source range of 50–80 °C. • The cooling capacity and COP reach 4579 W and 0.673, respectively. • The hybrid system provides a promising solution for efficient energy utilization. [ABSTRACT FROM AUTHOR]