Research On The Performance Of A Box Fire Hose Heat Pump Drying System With Exhaust And Bypass

Fire hoses are widely used in municipal fire prevention,forest fire prevention,industrial and mining enterprises,farmland irrigation,and other fields.According to the relevant national regulations,the hose should be dried in a timely manner after use and stored in a cool place to ensure its service life and safety.But at present,the cleaned hoses are still dried by laying flat on the ground,hanging on the outside wall,or using the traditional dryers,which are greatly affected by the external environment and have low drying efficiency.it is difficult to meet the needs of safety,energy saving,and rapid drying fire hose.To address the low level of intelligence of existing hose winding and drying equipment and the time-consuming and labor-intensive natural drying process,this article from the energy-efficient utilization and the actual demands of drying,based on air source heat pump technology designed and developed a box fire hose heat pump drying system with exhaust and bypass function.This system not only realizes the automatic retraction of the hose but also shortens the drying period and improves the drying efficiency compared to traditional air-drying methods.In comparison to traditional dryers,it reduces energy consumption and increases energy utilization efficiency.The exhaust and bypass strategies solve the problems of the traditional closed heat pump drying system,such as high air humidity at the outlet of the drying box in the early drying stage,less latent heat absorbed by the evaporator in the late drying stage,and lower unit efficiency.Heat pump technology has been fully utilized in the drying industry.The research content and main conclusions of this article are as follows:（1）A box type fire hose heat pump drying system with exhaust and bypass function was designed and fabricated,and the feasibility of the exhaust and bypass strategies was theoretically analyzed and verified.The stability of the equipment installation and the reliability of the operation were preliminarily tested,and the feasibility of drying fire hoses with air source heat pumps was verified.（2）Through the drying characteristic test of the fire hose,the drying rate of the hose was 0.1h^-1,and the dry base moisture content of the hose was 10%as the basis for dividing drying stage of the fire hose.Logarithmic model was determined to be the most suitable model to describe the drying characteristics of fire hose by test data and this model can effectively predict the moisture ratio change of fire hose under different drying conditions.（3）The feasibility of the bypass and exhaust strategies was verified by the performance test of the drying system.The results showed that the coefficient of performance were 4.1 and 3.63,respectively,which were 2.8%and 8.5%higher than the traditional closed drying mode.The specific moisture extraction rates were2.308kg/k Wh and 2.066kg/k Wh,respectively,which were 13.5%and 24.5%higher than the traditional closed drying mode,respectively.The results show that the combined exhaust and bypass drying mode was more energy-efficient than the traditional closed heat pump drying mode.（4）The TRNSYS simulation model of the air-source heat pump drying system under exhaust and bypass operation mode was constructed.The combined operation mode of exhaust and bypass was optimized.The energy power consumption,coefficient of performance,and specific moisture extraction rates of the system were compared and analyzed,and the optimal drying condition of the fire hose heat pump drying system was determined when the air supply temperature was 55℃,the air supply speed was1m/s,the exhaust proportion was 2/9 and the bypass rate was 50%.The specific moisture extraction rates at the early drying stage and late drying stage were2.313kg/k Wh and 2.186kg/k Wh,respectively.