Heat pump system for heating drying medium and recovering waste heat in stepped mode

Abstract

The invention provides a heat pump system for heating a drying medium and recovering waste heat in a stepped mode. The heat pump system comprises a drying room, a drying medium flowing-in channel and a drying medium flowing-out channel, wherein the drying medium flowing-in channel and the drying medium flowing-out channel are communicated with the drying room. The heat pump system at least comprises two heat pump units. Each heat pump unit comprises a compressor, a condenser, a throttling valve and an evaporator. The condensers are arranged in the drying medium flowing-in channel. At least one evaporator is arranged in the drying medium flowing-out channel. The condensers in all the heat pump units are sequentially arranged in the drying medium flowing-in channel from an inlet to the drying room. The evaporators corresponding to all the heat pump units and located in the drying medium flowing-out channel are sequentially arranged from a drying medium flowing-out opening to the drying room. The temperature difference, the pressure difference and the compression ratio between the condensers and the evaporators of all the heat pump units are reduced, the energy efficiency ratio of each heat pump unit is increased, the energy efficiency ratio of the whole heat pump system is increased, and the working condition of a compressor unit is improved.

Description

technical field [0001] The invention relates to the technical field of dry heat pump design, in particular to a heat pump system for cascaded heating of drying medium and cascaded recovery of waste heat. Background technique [0002] A heat pump is a thermal device powered by a compressor that transfers heat from a low-temperature heat source to a high-temperature heat source through the evaporation of a refrigerant in a low-temperature heat source and condensation in a high-temperature heat source. [0003] The low-temperature heat source usually used for the heat absorption of the evaporator of the heat pump device is the medium around us, such as air, river water, lake water, groundwater, etc., or it can be the waste gas, waste water and waste liquid with waste heat generated in the industrial production process. [0004] Generally, heat pumps are used to heat media such as air, water, oil, etc., and these media are the high-temperature heat sources of the heat pump. [...

AI Technical Summary

Problems solved by technology

[0022] However, the current application of heat pumps still faces the problem of low energy efficiency.

Drying and other operations usually require drying media such as air, which has a relatively large temperature rise to greatly reduce the relative humidity of the air to obtain a strong moisture absorption capacity, which requires the condenser of the heat pump system currently used to have a high condensation capacity. temperature; but as mentioned earlier, higher condensing temperature and condensing pressure will inevitably reduce the energy efficiency ratio of the heat pump system

And if there is not a high enough energy efficiency ratio, it will be difficult to digest the equipment costs, electricity costs and other costs of the heat pump system, making it difficult for the heat pump system to operate

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