Three-casing-pipe heat exchanger and heat pump water heater using same

Abstract

The invention discloses a heat pump water heater using a three-casing-pipe heat exchanger. The heat pump water heater comprises a three-casing-pipe heat exchanger, a compressor, an air-side heat exchanger, a throttling element and a water tank; the three-casing-pipe heat exchanger comprises an inner-layer pipe, a middle-layer pipe sleeved outside the inner-layer pipe and an outer-layer pipe sleeved outside the middle-layer pipe; a first annular channel is formed between the inner-layer pipe and the middle-layer pipe; a second annular channel is formed between the middle-layer pipe and the outer-layer pipe; the compressor, the air-side heat exchanger, the throttling element and the first annular channel are communicated through pipelines, so as to form a working medium circulation loop; the water tank is connected with the inner-layer pipe through the pipeline, so as to form a water circulation loop; a water inlet and a water outlet are formed in the second annular channel; a hot water supply pipe is connected between the water outlet and the water tank; and an external water supply opening is formed in the water tank. With the adoption of the heat pump water heater using the three-casing-pipe heat exchanger provided by the invention, the energy can be efficiently saved, and the comfort degree of user in water utilization can be improved well.

Description

technical field [0001] The invention relates to the technical field of high-temperature heat pumps, in particular to a heat pump water heater using a three-pipe heat exchanger. Background technique [0002] With the improvement of environmental protection and energy-saving awareness, household heat pump water heaters have been widely used in families due to their good energy-saving effect, safety and sanitation. [0003] Existing circulating heating heat pump water heaters generally include a compressor, an air-side heat exchanger, a throttling element, a water-side heat exchanger, and a water tank. The heat exchangers are connected through pipelines to form a working medium circulation loop, and the water tank and the water-side heat exchanger are connected through pipelines to form a water circulation heating loop. However, the current commonly used heat pump water heaters with circulating heating have the following problems: First, most of the existing water-side heat ex...

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Problems solved by technology

However, the current commonly used heat pump water heaters with circulating heating have the following problems: First, most of the existing water-side heat exchangers adopt a double-pipe casing structure, that is, the outer pipe covers the inner pipe, and an annular passage is formed between the inner pipe and the outer pipe. There is a working fluid flowing in the annular channel, but this structure only uses the heat transferred from the working fluid to the inner pipe to heat the water, while the heat transferred from the working fluid to the outer pipe is wasted in the air due to poor insulation, and the structure The heat exchange area is small, the comprehensive heat exchange efficiency is low, the condensation temperature of the working fluid is high, and the energy consumption is high; the second is that the user's water comfort is poor, which is because the current common water circulation heating method heat pump water heater uses cold water directly into the water tank, When the water consumption is large and the water replenishment is rapid, the added cold water will mix with the hot water stored in the water tank, and the heat pump water heater fails to heat the water in the water tank in time, resulting in low outlet water temperature, which affects the user's water comfort. Since the hot water flowing out of the external water supply port of the water tank is directly mixed with the cold water for the user to use, the hot water consumption of the water tank is fast, and the user's water comfort is further affected

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