Methods and systems for defrosting a transport climate control system evaporator

Patent metadata

Field	Value
Publication number	US-11970048-B2
Application number	US-202117407561-A
Country	US
Kind code	B2
Filing date	Aug 20, 2021
Priority date	Aug 20, 2021
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A transport climate control system for providing climate control to a climate controlled space of a transport unit. The transport climate control circuit includes a compressor, an evaporator and at least two fans. The transport climate control circuit also includes a controller for controlling the transport climate control circuit and for defrosting the evaporator coil. When a defrost event is triggered, the controller instructs the transport climate control circuit to supply heat to or around one section of the evaporator coil, and independently controls each of the at least two fans to move the air around the evaporator coil in a controlled direction so that heat from the one section of the evaporator coil is used to convectively heat the inlet of the evaporator coil.

First claim

What is claimed is:

1. A transport climate control system for providing climate control to a climate controlled space of a transport unit, the transport climate control system comprising:
a transport climate control circuit comprising:
a compressor that compresses a working fluid passing through the transport climate control circuit,
an evaporator that absorbs heat from the climate controlled space and evaporates the working fluid, said evaporator comprising:
an evaporator coil having an inlet side for receiving the working fluid from an inlet of the evaporator coil, the inlet side extending from a first side of the evaporator coil to a second side of the evaporator coil, and an outlet side for returning the working fluid to an outlet of the evaporator coil, the outlet side extending from the first side of the evaporator coil to the second side of the evaporator coil,
at least two fans that control air flow around the first side of the evaporator coil and the second side of the evaporator coil,
an electric heating device positioned on the outlet side of the evaporator coil and only extends between the first side and the second side on the outlet side of the evaporator coil, and
a damper that moves between at least an open position and a closed position to separate the evaporator from the climate controlled space and to control an amount of the air flow between the evaporator and the climate controlled space,

a controller configured to control the transport climate control circuit and configured to defrost the evaporator coil by:
closing the damper when a defrost event is triggered to separate the evaporator from the climate controlled space,
instructing the transport climate control circuit to supply heat to or around the outlet side of the evaporator coil by turning on the electric heating device to generate heat, and
independently controlling each of the at least two fans to move the air around the evaporator coil in a controlled direction so that heat from the electric heating device at the outlet side of the evaporator coil at one of the first side or the second side of the evaporator coil is used to convectively heat frost formed on the inlet side of the evaporator coil.

2. The transport climate control system of claim 1 , wherein instructing the transport climate control circuit to supply heat to or around the outlet side of the evaporator coil includes instructing the transport climate control circuit to direct hot gas from the compressor to the evaporator coil.

3. The transport climate control system of claim 1 , wherein the electric heating device comprises a heating fin configured to evenly distribute the heat from the supply of heat along the first side and the second side of the evaporator coil.

4. The transport climate control system of claim 1 , wherein at least one of the at least two fans is configured to operate in a positive air flow direction by blowing air towards the evaporator coil and at least one of the at least two fans is configured to operate in a negative air flow direction by drawing air from the evaporator coil.

5. The transport climate control system of claim 1 , wherein at least a third fan is provided to further control air flow around the evaporator coil of the evaporator.

6. The transport climate control system of claim 1 , wherein the controller is configured to monitor the evaporator coil of the evaporator by monitoring at least one of evaporator coil temperature data and evaporator pressure data across the evaporator coil and automatically defrost the evaporator coil.

7. A method for defrosting an evaporator of a transport climate control circuit of a transport climate control system that provides climate control to a climate controlled space of a transport unit, the transport climate control circuit including a compressor, an evaporator that includes an evaporator coil having an inlet side for receiving a working fluid from an inlet of the evaporator coil, the inlet side extending from a first side of the evaporator coil to a second side of the evaporator coil, and an outlet side for returning the working fluid to an outlet of the evaporator coil, the outlet side extending from the first side of the evaporator coil to the second side of the evaporator coil, at least two fans, an electric heating device, and a damper that moves between at least an open position and a closed position to separate the evaporator from the climate controlled space and to control an amount of the air flow between the evaporator and the climate controlled space, the method comprising:
a controller of the transport climate control system detecting a defrost event condition;
upon detecting the defrost event condition:
closing the damper when a defrost event is triggered to separate the evaporator from the climate controlled space,
supplying heat to or around the outlet side of the evaporator coil by turning on the electric heating device to generate heat, wherein the electric heating device is positioned on the outlet side of the evaporator coil and only extends across the evaporator coil between a first side and a second side on the outlet side of the evaporator coil;

independently controlling a first fan of the at least two fans to move air around the evaporator coil in a first controlled direction so that heat from the electric heating device at the outlet side of the evaporator coil at one of the first side or the second side of the evaporator coil is used to convectively heat frost formed on the inlet side of the evaporator coil, and
independently controlling a second fan of the at least two fans to move air around the evaporator coil in a second controlled direction so that heat from the other side of the evaporator coil is only used to convectively heat the inlet side of the evaporator coil.

8. The method for defrosting the evaporator of claim 7 , wherein independently controlling the first fan of the at least two fans to move air around the evaporator coil in the first controlled direction includes the first fan moving air from the inlet side of the evaporator coil at the first side of the evaporator coil to the outlet side of the evaporator coil at the first side of the evaporator coil and from the outlet side of the evaporator coil at the second side of the evaporator coil to the inlet side at the second side of the evaporator coil.

9. The method for defrosting the evaporator of claim 7 , wherein independently controlling the first fan of the at least two fans to move air around the evaporator coil in the first controlled direction includes the first fan moving air from the outlet side of the evaporator coil at the first side of the evaporator coil to the inlet side of the evaporator coil at the first side of the evaporator coil.

10. The method for defrosting the evaporator of claim 7 , further comprising controlling heating around the evaporator until the evaporator coil is defrosted.

11. The method for defrosting the evaporator of claim 7 , further comprising;
monitoring an evaporator parameter of the evaporator coil; and
supplying heat to the evaporator based on the evaporator parameter.

12. The method for defrosting the evaporator of claim 11 , wherein monitoring the evaporator parameter includes monitoring at least one of evaporator coil temperature data and evaporator pressure data across the evaporator coil.

13. The transport climate control system of claim 1 , wherein the frost formed at the inlet side of the evaporator coil is not directly heated by the electric heating device.

14. The transport climate control system of claim 1 , wherein the electric heating device is controlled to a temperatu

Assignees

• Thermo King Llc

Inventors

• Srichai Panayu Robert
• Ludwig Bradley M
• Vath Christopher John

Classifications

• B60H1/321 Primary

  for preventing the freezing of a heat exchanger · CPC title

• B60H1/3232 Primary

  particularly adapted for load transporting vehicles (B60H1/3226 takes precedence) · CPC title

• B60H2001/3288

  Additional heat source · CPC title

• B60H2001/3282

  to control the air flow · CPC title

• B60H2001/00961

  comprising means for defrosting outside heat exchangers · CPC title