According to the current application status and development level of heat pump technology, through the comprehensive analysis and research of related literatures, we think that the key technologies of heat pump to achieve the sustainable development of resources and environment should focus on the following aspects: 1) Efficient and reliable long life Research and development of key equipment for low-cost heat pump units, research on reliable energy-saving capacity adjustment and operation control methods, and further increase the potential and advantages of heat pumps in energy saving. As in the small heat pump units, the current excellent performance of screw compressors and scroll compressors are replacing reciprocating compressors to improve the adiabatic efficiency of heat pump compressors. Research on heat transfer equipment development and heat transfer characteristics also plays an important role in improving the performance of heat pump units and reducing the heat pump unit costs. At present, in addition to continuing the study of enhanced heat transfer, an important issue that needs to be carried out is to study the flow and heat transfer characteristics of refrigerant in the plate heat exchanger for different operating parameters of different working fluids and heat pumps. With the continuous expansion of heat pump applications, the development of large and medium heat pump units has become an urgent problem to be solved in the field of heat pump applications. 2) To carry out a variety of heat source heat pump system theory and application research, the current focus should be carried out to ground heat exchanger ground source heat pump theoretical research. Air source heat pump has been widely used in the field of air conditioning, but its performance is restricted by the seasonal temperature variation of outdoor weather conditions, the cooling capacity and heating capacity are difficult to adapt to the building's cooling load and heat load, Frosting frost and other issues, so that the scope and scope of its application is subject to a great extent. The surface water of the rivers, lakes and seas is undoubtedly an alternative way of heat pump heat source. However, its application is also limited by the water source conditions and meteorological conditions, and its application fields and scope have some limitations. Processed domestic sewage and industrial waste water as heat pump low-temperature heat source, should be a research direction worthy of attention. Under normal circumstances, the underground water temperature buried at a certain depth of the ground can be maintained around the annual average temperature in the year. From the point of view of thermodynamic cycle analysis, the groundwater source heat pump has higher circulation efficiency than other ground source heat pumps some. In recent years, underground water source heat pump can be said in our country has received unprecedented attention. However, since the problem of recharge of groundwater is a technical problem that has not yet been effectively solved so far, groundwater resources may be caused by over-exploitation of groundwater, environmental geology problems such as water level declines and land subsidence, as well as possible groundwater recharge The secondary pollution problem should be given enough attention. For a country like China with a shortage of water resources, the protection of groundwater resources is a major issue that concerns sustainable development. Therefore, the popularization and application of groundwater sources should be maintained in a cautious manner. The use of buried ground source heat pump mode, because the soil surface below a certain depth of the soil temperature stability and annual temperature is about equal to the annual average temperature, respectively, in summer and winter provide relatively low condensation temperature and high evaporation temperature, which can be obtained Better energy savings than air-source heat pumps, while avoiding the air-source heat pump's under-the-hood efficiency issues that make it possible to get a wider range of applications. Secondly, because it does not directly extract groundwater, it can effectively avoid the destruction of groundwater resources, a kind of reasonable way to develop and utilize geothermal resources. Although ground heat exchangers are affected by the rate of heat exchange between the fluid in the underground pipe and the soil, large heat exchanger area needs to be arranged and high investment cost, but ground source heat pumps are still recognized and promising for the present and future Energy-saving devices and systems, the international air conditioning and refrigeration industry is one of the hot topics. 3) Attach importance to and accelerate the theoretical research and application development of natural working fluid. At present, the refrigerant used in heat pump system in our country is mainly R22 and R134a, and R22 is a kind of HCFC working fluid, which is in need of refrigeration service for phase-out. Hydrogen Fluorocarbons, R134a, are controlled greenhouse gases due to their high GWP. In Japan, the United States and other countries used mixed services, such as R410a are actually hydrofluorocarbons working fluid, although its ODP = 0 but still has a high GWP value. In addition, the heat pump system used in building air conditioning system, generally require higher condensation temperature and greater temperature changes, which is also synthetic refrigerant used in high temperature heat pump a major difficulty. Synthetic refrigerants, the volume of cooling capacity decreases with increasing temperature, such as R134a, used to replace R22, the volume of cooling capacity decreased by about 30%. In terms of the long-term safety of the environment, we should try our best to avoid using the unnatural working fluids that will be discharged to the biosphere to the greatest extent. It is a very safe choice to re-use natural working fluids and may also be a choice that we have to make. However, some natural working fluids, which are used in the heat pump field, may provide a good opportunity to solve the technical problems of medium and high temperature heat pumps. Such as the transcritical carbon dioxide cycle, the higher compressor discharge temperature and the greater temperature glide of carbon dioxide in the gas cooler, creating favorable conditions for the recovery of exhaust heat. Conventional refrigerant heat pump can only get no more than 55 degrees Celsius hot water, but the carbon dioxide heat pump system can get 90 degrees Celsius or even higher temperature hot water, so its application will be more broad. 4) Study on Gas-driven Heat Pumps In China, the primary energy used to generate electricity still accounts for the largest proportion of coal. Strictly speaking, China's coal-dominated energy structure determines that electricity is not a clean energy. As part of China's energy restructuring strategy, China will gradually increase the proportion of natural gas in the energy mix. The use of natural gas-driven heat pump, natural gas is an efficient terminal utilization, but also a greenhouse gas minus the row and the environmental protection of hot and cold air source way. In addition to the above, the research on heat pump applications such as energy storage technology and dehumidification cooling technology is also an effective measure to improve the overall energy saving effect of heat pumps. In short, heat pump technology theory and application of research, should take into account the relationship between resources, environment and economic benefits. For now, efforts should be made to expand the application and promotion of ground-source heat pumps, which should speed traditional wages, as far as renewable energies and low-grade energy applications are concerned. In view of the long-term impact on the environment and the rational utilization of resources, heat pump technology that uses renewable energy as a heat source, clean energy as a driving force and natural working fluid will be an effective solution to the cold and heat sources of air conditioning.
Fiberglass screens have become a popular choice for homeowners seeking a reliable and durable solution for their windows and doors. These screens are made from a high-quality fiberglass material that offers numerous benefits. With their fine mesh construction, fiberglass screens effectively keep out insects and pests while allowing fresh air and natural light to flow through. They are also resistant to corrosion, rust, and fading, making them ideal for long-term use. Additionally, fiberglass screens are easy to install and maintain, providing a practical and cost-effective solution for creating a comfortable and bug-free environment indoors. Whether you're looking to improve ventilation or protect against unwanted pests, fiberglass screens offer a reliable and visually appealing option.
Fiberglass Insect Screen,Fiberglass Insect Window Screen,Fiberglass Insect Screen Roll Net,Fiberglass Insect Window Net
Jinwu Glass Fiber Co., Ltd , https://www.jwglassfiber.com