ZEMCH 2019 International Conference Proceedings April.2020 | Page 405
storage tank. The heat pump condenser inlet and outlet temperatures and the 3‐way valve pass‐through
temperature are shown in Figure 2. After 90 minutes of operation, the temperature of the produced hot
water converges to 70 ° C.
Figure 2. Temperature variations in each points
3.1.3. Volume and temperature of hot water produced
The temperature of the hot water flowing into the heat storage tank is 70 ℃ after 90 minutes of
operation, and the hot water volume is 20ℓ/min. Accordingly, the required vacuum pressure and steam
generation amount are shown in Table 2.
Table 2. Condition of hot water produced
Temperature
70℃
Water flow rate
20ℓ/min(1.2㎥/h)
Required vacuum
pressure
0.3077 atm
Vapor volume
5,917 ㎥/h
5. Conclusions
In this study, the mechanism for the optimization of seawater desalination system using heat pump
was analyzed through previous research analysis and experiment. The analysis results are as follows.
Compared with the existing MED method, the seawater desalination system using a heat pump can be
applied in a small scale, and the system can be easily constructed because heat is exchanged through
air when condensing steam.
Seawater desalination system using heat pump produces hot water of 70 ℃ by using condenser heat,
converts it into steam through vacuum pump, and heat‐exchange with low temperature air of
evaporator to produce fresh water.
By installing 3Way valve, hot water of 60 ℃ can be produced quickly in 20 minutes after the operation
of the device, and it can produce hot water of 70 ℃ continuously after 90 minutes. In order to convert
the produced 70 ℃ hot water into steam, the pressure below 0.3077 atm using a vacuum pump is
required.
Mechanism Analysis of Seawater Desalination System using a Heat Pump
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