Geothermal heat utilization system and geothermal heat utilization method

Patent metadata

Field	Value
Publication number	US-10845129-B2
Application number	US-201815934104-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Mar 31, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A geothermal heat utilization system includes a heat source well facility, a heat source device having a refrigeration cycle including a compressor, a condenser, an expanded portion, and an evaporator, a primary refrigerant circuit that is connected to a first unit which is one of the condenser and the evaporator of the heat source device, heat exchange being able to be performed between the first unit and the well-side pipe, a secondary refrigerant circuit that is connected to a second unit which is the other of the condenser and the evaporator of the heat source device, heat exchange being able to be performed between the second unit and a load, and a mode switching unit that switches between a cold heat storage operation mode in which the primary refrigerant circuit is connected to the evaporator and the secondary refrigerant circuit is connected to the condenser and a cold heat discharge operation mode in which the primary refrigerant circuit is connected to the condenser and the secondary refrigerant circuit is connected to the evaporator.

First claim

What is claimed is:

1. A geothermal heat utilization system comprising:
a heat source well facility including a hot water well, a cold water well, a well-side pipe that connects the wells, and a pump provided in the well-side pipe;
a heat source device having a refrigeration cycle including a compression unit, a condenser, an expansion unit, and an evaporator;
a primary refrigerant circuit that is connected so as to pass through only a first unit out of the first unit and a second unit, the primary refrigerant circuit capable of performing heat exchange between the first unit and the well-side pipe by the first refrigerant circulated between the first unit and the well-side pipe, wherein the first unit is one of the condenser and the evaporator of the heat source device and the second unit is the other of the condenser and the evaporator of the heat source device;
a secondary refrigerant circuit that is connected so as to pass through only the second unit out of the first unit and the second unit, the secondary refrigerant circuit capable of performing heat exchange between the second unit and a load by the second refrigerant circulated between the second unit and the load;
a plurality of opening and closing valves; and
a mode switching unit that is connected to each valve of the plurality of opening and closing valves so as to be capable of transmitting a control signal to each valve and controls each valve so as to switch between a cold heat storage operation mode in which the primary refrigerant circuit is connected so as to pass through the evaporator and the secondary refrigerant circuit is connected so as to pass through the condenser and a cold heat discharge operation mode in which the primary refrigerant circuit is connected so as to pass through the condenser and the secondary refrigerant circuit is connected so as to pass through the evaporator.

2. The geothermal heat utilization system according to claim 1 , further comprising a cooling tower, and a cooling tower-side refrigerant circuit connected so as to pass through the cooling tower.

3. The geothermal heat utilization system according to claim 2 , wherein the mode switching unit controls each valve so as to switch the secondary refrigerant circuit to a first auxiliary refrigerant circuit in which heat exchange is able to be performed between the cooling tower-side refrigerant circuit and the condenser in the cold heat storage operation mode.

4. The geothermal heat utilization system according to claim 3 , wherein the mode switching unit controls each valve so as to switch the primary refrigerant circuit and the secondary refrigerant circuit to a secondary auxiliary refrigerant circuit in which heat exchange is able to be performed between the cooling tower-side refrigerant circuit and the well-side pipe in the cold heat storage operation mode.

5. The geothermal heat utilization system according to claim 2 , wherein the mode switching unit controls each valve so as to switch the primary refrigerant circuit and the secondary refrigerant circuit to a secondary auxiliary refrigerant circuit in which heat exchange is able to be performed between the cooling tower-side refrigerant circuit and the well-side pipe in the cold heat storage operation mode.

6. The geothermal heat utilization system according to claim 5 , further comprising:
an injected water thermometer that is provided in the well-side pipe and detects a temperature of water injected into the cold water well;
an outside air thermometer that detects an outside air temperature; and
a mode determination unit that compares the outside air temperature with the injected water temperature and determines whether the outside air temperature is lower than the injected water temperature,
wherein when the mode determination unit determines that the outside air temperature is lower than the injected water temperature, the mode switching unit controls each valve so as to perform switching to the second auxiliary refrigerant circuit.

7. The geothermal heat utilization system according to claim 2 , wherein:
in the cold heat discharge operation mode, the mode switching unit controls each valve so as to connect the secondary refrigerant circuit such that the secondary refrigerant circuit passes through the evaporator, and perform switching to a second expanded refrigerant circuit in which heat exchange is able to be performed between the evaporator, the load, and the well-side pipe, and
switch the primary refrigerant circuit to a first auxiliary refrigerant circuit in which heat exchange is able to be performed between the cooling tower-side refrigerant circuit and the condenser.

8. The geothermal heat utilization system according to claim 7 , further comprising:
an injected water thermometer that is provided in the well-side pipe and detects a temperature of water injected into the hot water well;
a load downstream side thermometer that is provided downstream of the load and detects a returned refrigerant temperature of a refrigerant returning from the load; and
a mode determination unit that compares the returned refrigerant temperature with the injected water temperature and determines whether the returned refrigerant temperature is higher than the injected water temperature,
wherein the mode determination unit controls each valve so as to perform switching to the second expanded refrigerant circuit and performs switching to the first auxiliary refrigerant circuit when the mode determination unit determines that the returned refrigerant temperature is higher than the injected water temperature.

9. The geothermal heat utilization system according to claim 1 , wherein the mode switching unit controls each valve so as to connect the secondary refrigerant circuit such that the secondary refrigerant circuit passes through the evaporator in the cold heat discharge operation mode, and perform switching to a first expanded refrigerant circuit in which heat exchange is able to be performed between the evaporator, the load, and the well-side pipe upstream of a location of heat exchange with the primary refrigerant circuit.

10. The geothermal heat utilization system according to claim 9 , further comprising:
a pumped water thermometer that is provided in the well-side pipe and detects a temperature of pumped water from the cold water well;
a load downstream side thermometer that is provided downstream of the load and detects a temperature of a returned refrigerant from the load; and
a mode determination unit that compares the return refrigerant temperature with the pumped water temperature and determines whether the returned refrigerant temperature is higher than the pumped water temperature,
wherein the mode switching unit controls each valve so as to perform switching to the first expanded refrigerant circuit when the mode determination unit determines that the returned refrigerant temperature is higher than the pumped water temperature.

11. A geothermal heat utilization method for performing a method comprising the steps of:
an operation mode selection step of selecting an operation mode of a geothermal heat utilization system as a cold heat storage operation mode or a cold heat discharge operation mode, the geothermal heat utilization system including a heat source well facility including a hot water well, a cold water well, a well-side pipe that connects the wells, and a pump provided in the well-side pipe, a heat source device having a refrigeration cycle including a compression unit, a condenser, an expansion unit, and an evaporator, a primary refrigerant circuit that is connected so as to pass through only a first unit out of the first unit and a second unit, the primary refrigera

Assignees

• Mitsubishi Heavy Ind Thermal Systems Ltd
• Kansai Electric Power Co
• Univ Osaka City
• Newjec Inc

Inventors

• Sakai Masanobu
• Fuchimoto Takeshi
• SAI Rinnichi
• Nakaso Yasuhisa
• SAKAE Shinsuke
• Nakao Masaki
• Nishioka Masatoshi
• Nakamura Kazuhiro

Classifications

• Y02E10/10

  Geothermal energy · CPC title

• F25B25/005

  using primary and secondary systems · CPC title

• Y02B10/40

  Geothermal heat-pumps · CPC title

• F25B2339/047

  Water-cooled condensers · CPC title

• F24T10/20

  using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells · CPC title