P2

Practice 2(12)

Object-oriented Programming：The vapor-compression refrigeration cycle simulator

Deadline: 2023.05.27

地源热泵分析

以SimVCCE分支B2023-2中的Python语言版本为基础进行设计，使其可计算如下地源热泵

A heat pump with R134a as the working fluid is used to keep a space at 25°C by absorbing heat from geothermal water that enters the evaporator at 50°C at a rate of 0.065 kg/s and leaves at 40°C.

The refrigerant enters the evaporator at 20°C with a quality of 23 percent and leaves at the inlet pressure as saturated vapor.

The refrigerant loses 300 W of heat to the surroundings as it flows through the compressor and the refrigerant leaves the compressor at 1.4 MPa at the same entropy as the inlet.

Determine

1. the degrees of subcooling of the refrigerant in the condenser (3.8°C)
2. the mass flow rate of the refrigerant (0.0194 kg/s)
3. the heating load and the COP of the heat pump (3.07kW, 4.68)
4. the theoretical minimum power input to the compressor for the same heating load (0.238kW)

注意

• 8th-11-43_geothermal.pdf文档中Win有误，应改为

编码(6分)

• 增加设备类(4)：the evaporator absorbing heat from geothermal water

  

• Condenser类(1)：增加the degrees of subcooling of the refrigerant计算

• VCCycle类(1)：增加the theoretical minimum power input计算

编码提示

"""
EvaporatorHeatExchange

the combined evporator and the water duct

                         ↓   iPort refrigerant
                   ┌─────┼─────┐
                   │ → ┌─┼─┐←  │
        oPortW   ← ┤ Q │ Z │ Q │← iPortW
                   │ → └─┼─┘←  │
                   └─────┼─────┘
                         ↓      oPort refrigerant

json example
 {
            "name": "EvaporatorHeatExchanger",
            "devtype": "EVAPORATOR_HEAT_EXCHANGER",
            "iPort": {},
            "oPort": {
                "x": 1.0
            },
            "iPortW": {
                "p": 0.1,
                "t": 50.0,
                "mdot":0.065,
                "refrigerant": "WATER"
            },
            "oPortW": {
                "p": 0.1,
                "t": 40.0,
                "refrigerant": "WATER"
            }
        }
"""
from components.port import Port

class EvaporatorHeatExchanger:

    energy = "QIN"
    devtype = "EVAPORATOR_HEAT_EXCHANGER"

    def __init__(self, dictDev):
        """ Initializes the EVAPORATOR_HEATIN_EXCHANGER """
        self.name = dictDev['name']
        self.iPort = Port(dictDev['iPort'])
        self.oPort = Port(dictDev['oPort'])
        self.iPortW = Port(dictDev["iPortW"])
        self.oPortW = Port(dictDev["oPortW"])

循环json文件(1分)

• compressor有散热

Markdown文档(5分)

设计方案(4)

以可计算Example11-1,Example11-5和练习中地源热泵的分析软件设计为对象，给出

• 面向对象程序设计的总体思路

• 设计方案的如下几个方面内容

  • 端口、设备、连接器、循环分析类设计(含UML类图）

  • 端口连接算法(含算法流程图)

    • 算法要点见class Connector的self.__add_node方法

  • 物性计算、循环计算算法(含算法流程图)

    • 算法要点见class VCCycle的 def __component_simulator(self)方法

  • 循环json数据文件设计

    • 端口、设备、端口连接关系

设计小结(1)

• 练习中遇到的问题、解决过程

文档提示

• 数学公式使用：LaTex

• UML、流程图使用: PlantUML文本描述

工作目录

 
 <学号-姓名-2>
     │ 
     │── README.md: Markdown文档
     | 
     |── <img> Markdown文档使用的图形文件
     |
     |── vccapp_json.py
     |
     |── <components> 
     |
     |── <vcc> 
     |
     |── <jsonmodel> 循环json数据文件
     |
     |── <result> 计算结果数据文件