Showing papers on "Heating system published in 2021"
TL;DR: In this article, the authors demonstrate the low mid-infrared radiative (mid-IR) emissivity characteristic of Ti3C2Tx MXene and then apply it for energy-free passive radiative heating (PRH) on the human body.
Abstract: Heating the human body to maintain a relatively constant temperature is pivotal for various human functions. However, most of the current heating strategies are energy-consuming and energy-wasting and cannot cope with the complex and changing environment. Developing materials and systems that can heat the human body precisely via an efficient energy-saving approach no matter indoors/outdoors, day/night, and sunny/cloudy is highly anticipated for mitigating the growing energy crisis and global warming but is still a great challenge. Here, we demonstrate the low mid-infrared radiative (mid-IR) emissivity characteristic of Ti3C2Tx MXene and then apply it for energy-free passive radiative heating (PRH) on the human body. Our strategy is realized by simply decorating the cheap nanoporous polyethylene (nanoPE) textile with MXene. Impressively, the as-obtained 12 μm thick MXene/nanoPE textile shows a low mid-IR emissivity of 0.176 at 7-14 μm and outstanding indoor PRH performance on the human body, which enhances by 4.9 °C compared with that of traditional 576 μm thick cotton textile. Meanwhile, the MXene/nanoPE textile exhibits excellent active outdoor solar heating and indoor/outdoor Joule heating capability. The three heating modes integrated in this wearable MXene/nanoPE heating system can be switched easily or combined arbitrarily, making this thin heating system able to heat the human body precisely in various scenarios like indoors/outdoors, day/night, and sunny/cloudy, providing multiple promising and energy-saving solutions for future all-day personal precision thermal management.
86 citations
TL;DR: In this article, a comprehensive survey on the potential of district heating systems in accommodating fluctuating heat supply and demand is proposed, and future directions for deploying the flexibility of district heat systems in northern China, including new heat sources, digitalization, demand side management, heat market deregulation, and energy policy reform.
66 citations
TL;DR: In this paper, a globally applicable source-to-sink methodology and analysis that matches geological storage capacity with energy demand is presented for the first time, with a focus on maintaining the existing gas distribution network.
65 citations
TL;DR: Based on the design concept of a fourth-generation smart pipe network system, a new TOTS (Two-supply/One-return, triple pipe structure) arrangement method for district heating systems was proposed in this article.
58 citations
TL;DR: In this article, the authors examined the technical feasibility of an off-grid energy system with short-term battery storage and seasonal hydrogen storage, comprising a water electrolyzer and a fuel cell.
56 citations
TL;DR: In this paper, the authors presented a first analysis of the energy demands for greenhouses transitioning from high pressure sodium (HPS) to LED lighting, providing a quantification of the total energy savings achieved by LEDs.
49 citations
TL;DR: In this article, the experimental and numerical investigation of a hydronic radiant floor heating system integrated with macro-encapsulated phase change materials (PCM) was carried out on a laboratory-scale by the University of Ferrara, Italy, within the H2020 European project IDEAS.
49 citations
TL;DR: The proposed CNN–LSTM algorithm can describe the complex change trend of the heating load and lead to a more accurate dynamic model of heating load with high nonlinearity and considerable thermal inertia delay, which can satisfy the field engineering applications' requirements in a more enhanced manner.
45 citations
TL;DR: In this article, a water tank and a borehole thermal energy storage system were selected as the short-term and long-term thermal energy storages, respectively, to solve the mismatch between data centres' heat supply and district heating systems' heat demands.
45 citations
TL;DR: In this article, the authors deal with thermodynamic modeling and multi-objective optimization of a new multi-generation energy system using geothermal as the primary energy source, which includes a Kalina cycle, a refrigeration unit, thermoelectric module, steam turbine, and heating unit.
43 citations
TL;DR: In this paper, a hybrid solar hot water and air source heat pump (HSAHP) combined heating system is proposed, which can realize various connection modes, such as SHW and ASHP parallel heating mode, series heating mode and preheating type connection mode.
TL;DR: In this article, compound parabolic concentrator (CPC) photovoltaic/thermal collectors (PV/T), absorption and ground source heat pumps are integrated to a novel space heating system for use in hotel and office buildings.
TL;DR: In this paper, the combined effect of using demand-side flexibility from buildings, by allowing for indoor temperature deviations (both up-and downward from the set-point), and supply side flexibility, by applying thermal energy storage (TES), on the operation of district heating (DH) systems is investigated.
TL;DR: Wang et al. as discussed by the authors studied the potential contribution to address climate change and the difference of provinces and urban-rural areas by 2035 with the considerations of both air pollutants and carbon emissions reduction using the China Regional Energy System Model.
TL;DR: In this article, the authors proposed a dynamic control strategy for substations based on online prediction and indoor temperature measurement, and the proposed strategy was applied in a practical district heating system (DHS).
TL;DR: In this article, the possibility of reusing and storing the waste heat by phase change material (PCM) in a sample greenhouse was studied experimentally, and the results showed that the effect of preheating the heater air gives rise to a 23.7% reduction of gas consumption and the effect is much more pronounced compared to the direct using of the stored heat.
TL;DR: The coal-fired system is placed as the worst among all heating systems regarding the impacts on the environment and renewable energy sources are the most preferred sources decreasing total emissions and air pollution.
TL;DR: In this article, the authors proposed an open-source dispatch sector coupling model (GRIMSEL-AH) to minimize energy system costs (social planner perspective) for heating and electricity supply in Switzerland with hourly and daily time resolution for electricity and heating respectively.
TL;DR: In this article, the authors investigated the development and assessment of a model-based predictive control strategy for the district heating system at the Drake Landing Solar Community (DLSC), in Okotoks (Alberta, Canada).
TL;DR: Using this technique of salty water heating, the production cost of freshwater is reduced by about 71% compared with the direct heating system and the exergoeconomic and enviroeconomic parameters of thedirect heating mechanism are more effective compared with those of the indirect heating mechanism.
Abstract: In this work, experimental work is presented on the performance of a hybrid solar distiller comprising solar still (SS) combined with parabolic trough solar collector (PTSC) using direct heating of salty water by the collector. In this technique, the salty water supplied to the SS is heated by passing it directly through the parabolic receiver without using heat transfer mediums that reduce the system efficiency. The study is carried out at different salty water depths inside the SS basin under hot climate conditions of Upper Egypt. The system performance is compared with a previous system using oil as a heat transfer medium between PTSC and still (indirect heating). The advantages of this technique are its ability to reduce initial salty water depth in the basin and avoid using the pumping system and heat exchanger compared to the direct heating. The performance of the proposed system is evaluated based on productivity, energy payback time (EPBT), exergy, enviroeconomic, and exergoeconomic methodologies. Findings illustrate that the present system rises the energy efficiency by about 12%, 27.5%, and 46% and the system exergy efficiency by about 14%, 30%, and 49% at salty water depth 15 mm, 10 mm, and 5 mm in the basin compared with the indirect heating system. Moreover, using this technique of salty water heating reduces the production cost of freshwater by about 71% compared with the direct heating system. The exergoeconomic and enviroeconomic parameters of the direct heating mechanism are more effective compared with those of the indirect heating mechanism.
TL;DR: In this article, the technical classification and operating principle of USTES, review the state-of-the-art of USTs worldwide, and also predicts the development trends of the technology.
Abstract: Underground seasonal thermal energy storage (USTES) facilitates the efficient utilization of renewable energy sources and energy conservation. USTES can effectively solve the mismatching characteristics of renewable energy heating system in terms of time, space and strength, which can transfer the renewable energy heating from the summer or transition seasons to the winter, and overcome the instability and low efficiency of the short-term thermal storage system. This research describes the technical classification and operating principle of USTES, reviews the state-of-art of USTES worldwide, and also predicts the development trends of the technology. It reveals that USTES has significant economic, social and environmental benefits. However large heat loss and low solar fraction are still the common challenges for large-scale applications. More work should be carried out on fundamental research including overall design and parameter matching optimization, heat loss mechanism, heat and moisture transfer properties. Moreover, the characteristic and performance of unsteady and transient heat transfer in complex underground environment, and their control strategies of the USTES have been also the most pressing problems. In addition, the supporting policy should be strengthened in planning formulation, legislative support, operation supervision, standard formulation and incentive measures to guide an orderly, healthy and sustainable development of USTES.
TL;DR: In this article, the authors explored the method of establishing a state-space model of a variable-flow radiant heating system without selecting and applying extensive measurement data and the application of the model predictive control method to its control optimization.
TL;DR: It is shown that considering the community of buildings as a single entity, the novel model predictive control can be efficiently used for minimizing the energy cost of the community that has various sources of energy generation, conversion and storage, including significant non-linear interactions.
TL;DR: A long-term co-optimization planning model for an IEHS based on independent load blocks is proposed and a parallel Benders decomposition algorithm combined with the sequential bound-tightening procedure is proposed to efficiently obtain high-quality solutions.
TL;DR: In this article, a Li-ion battery heating method based on micro heat pipe array (MHPA) is proposed to heat battery packs from −30°C to 0°C within 20 minutes, with a maximum temperature difference of less than 3.03°C.
Abstract: Deterioration of charge and discharge performance of vehicle-mounted power lithium-ion (Li-ion) batteries in low-temperature environments and low heat dissipation in high temperature affects the application of electric vehicles in cold areas. Therefore, low-temperature thermal management system (TMS) of lithium batteries is particularly important. A Li-ion battery heating method based on micro heat pipe array (MHPA) is proposed in this study. A three-dimensional model is established using COMSOL Multiphysics software to analyze temperature distribution inside the battery during low-temperature heating. Results suggested that a single heating system based on MHPA can heat battery packs from −30°C to 0°C within 20 minutes and the temperature distribution in the battery pack is uniform, with a maximum temperature difference of less than 3.03°C. In addition, the interaction between heat dissipation and heating modules in the lithium battery pack of the integrated TMS based on MHPA is analyzed. Simulation results showed that heat dissipation components will negatively affect the temperature rise at low temperatures and heating components will enhance the high-temperature heat dissipation effect of the battery pack. The research results will be useful in the design of MHPA applied to the TMS of Li-ion battery packs.
TL;DR: In this article, a low carbon district heating system that features a low return water temperature, use of low grade waste heat as the main heat source, long distance heat transmission with a large temperature difference, distributed peak heating load addition by natural gas and heat-power decoupling with heat pump and thermal storage.
TL;DR: In this article, the authors presented three new LHTES integrating layouts where the Latent Heat Thermal Energy Storage (LHTES) unit is connected with the de-superheater of the main heat pump (Case 2), the condenser of a cascaded booster heat pump cycle (Case 3), or a combination of using both the deheater and the booster cycle.
TL;DR: Evaluating the impact of different control schemes on the energy flexibility of residential buildings can be beneficial to guide the control system design of new buildings or control retrofits of existing buildings that consider better grid-building interactions for the future.
Abstract: Buildings can be operated in an energy-flexible manner while respecting occupant thermal comfort. This energy flexibility of building operations, both in time and quantity, can be harnessed by the electrical grid for load balancing. In the context of smart grid and intelligent buildings, the concept of energy flexibility in buildings broadens the existing demand management thinking from the top-down one-way control to two-way communications. This paper, extending studies on thermostat controls of heating and air conditioning systems for demand response, evaluates the impact of different control schemes on the energy flexibility of residential buildings. Two control strategies, Model Predictive Control (MPC) and Rule-Based Control (RBC), are investigated for a space heating system using co-simulation studies. Four indicators are introduced and adapted from the literature to assess the control performances of the strategies. Simulation results show that different flexibility indicators favour different control strategies in this case study. For demand response events of four hours, the MPC strategy presents two to three times of flexible energy than that of RBC. MPC also delivers 20% more of maximum power reduction during the events against RBC. The RBC strategy, on the other hand, is twice of MPC for flexible energy efficiency. This evaluation work can be beneficial to guide the control system design of new buildings or control retrofits of existing buildings that consider better grid-building interactions for the future.
TL;DR: A model-free algorithm belonging to the Deep Reinforcement Learning (DRL) class, Soft Actor-Critic, was implemented to control the supply water temperature to radiant terminal units of a heating system serving an office building, leading to an improvement of indoor temperature control.
Abstract: Recently, a growing interest has been observed in HVAC control systems based on Artificial Intelligence, to improve comfort conditions while avoiding unnecessary energy consumption. In this work, a model-free algorithm belonging to the Deep Reinforcement Learning (DRL) class, Soft Actor-Critic, was implemented to control the supply water temperature to radiant terminal units of a heating system serving an office building. The controller was trained online, and a preliminary sensitivity analysis on hyperparameters was performed to assess their influence on the agent performance. The DRL agent with the best performance was compared to a rule-based controller assumed as a baseline during a three-month heating season. The DRL controller outperformed the baseline after two weeks of deployment, with an overall performance improvement related to control of indoor temperature conditions. Moreover, the adaptability of the DRL agent was tested for various control scenarios, simulating changes of external weather conditions, indoor temperature setpoint, building envelope features and occupancy patterns. The agent dynamically deployed, despite a slight increase in energy consumption, led to an improvement of indoor temperature control, reducing the cumulative sum of temperature violations on average for all scenarios by 75% and 48% compared to the baseline and statically deployed agent respectively.
TL;DR: In this article, a photovoltaic thermal heat pump system was introduced to improve the comprehensive energy efficiency and reduce the operation energy consumption of the heat source system, which provided a new idea for the energy saving reconstruction of clean district heating.