Power saving system and method for a refrigeration system, providing for short term response to reduce ripples on a power grid

• US 9,263,891 B2
• Filed: 12/14/2009
• Issued: 02/16/2016
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: Danfoss A/S
• Original Assignee: Danfoss A/S
• Inventors: Jensen, Helge Vandel, Thybo, Claus, Bram, Leo, Kobberoe, Ejner
• Primary Examiner(s): VON BUHR, MARIA N
• Application Number:
  US13/139,049
• Publication Number:
  US 20110313588A1
• Time in Patent Office: 2,255 Days
• Field of Search: 700/275, 700/276, 700/286, 700291-296, 700/299, 700/300, 323/234, 323/299, 323/304
• US Class Current: 1/1
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25D 29/00 Arrangement or mounting of control or safety devices
• CPC Class Codes: H02J 2310/14 The load or loads being home appliances
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/242 Home appliances
• CPC Class Codes: Y04S 20/244 the home appliances being or involving heating ventilating and air conditioning [HVAC] units

Abstract

The present invention relates to a method and a system to reduce losses of energy due to ripples, especially at the power grid, the ripples being short term power shortages or excess power. The method is based on the idea of shutting off energy consuming devices during a period of power shortage, if their operation is not necessary, and optionally to turn on such energy consuming devices during periods of excess power, if energy may be stored in them, especially when energy may be stored as some physical parameter or variable, being a part of the operation of the energy consuming devices, such as the temperature of a freezer.

Claims

1. A method of managing, regulating and/or controlling energy consumed by a refrigeration system comprising at least one compressor feeding a plurality of refrigeration entities to provide short term responses to ripples on a power grid, where the refrigeration entities of the plurality of refrigeration entities may each increase or decrease a physical parameter, and where the refrigeration entities of the plurality of refrigeration entities are each set to operate within a range of the physical parameter defined by a minimum physical parameter and a maximum physical parameter, the method comprising the steps of receiving a message from a controller either to decrease or to increase the energy consumption so as to provide a short term response to reduce ripples on the power grid, and where the decrease or increase in the energy consumption is achieved by changing the physical parameter such that each refrigeration entity of the plurality of refrigeration entities being in the process of decreasing its physical parameter is instructed to stop decreasing its physical parameter when the message is to decrease the energy consumption, and each refrigeration entity of the plurality of refrigeration entities being in the process of increasing its physical parameter is instructed to start decreasing its physical parameter when the message is to increase the energy consumption, while the at least one compressor ensures circulation of refrigerant to the extent needed by the refrigeration system.

2. The method according to claim 1, wherein each energy consuming device overrules the message and changes stage when reaching the minimum or maximum physical parameter, so that the energy consuming device changes to decrease the physical parameter when it reaches the maximum physical parameter and changes to increase the physical parameter when it reaches the minimum physical parameter.

3. The method according to claim 2, wherein the physical parameter is a temperature.

4. The method according to claim 3, wherein the energy consuming devices are either refrigeration or freezing devices.

5. The method according to claim 1, wherein the message to decrease energy consumption is provided by the controller when the total energy delivered by the power grid increases above an expected delivered energy span, and the message to increase energy consumption is provided by the controller when the total energy delivered by the power grid decreases below an expected delivered energy span.

6. The method according to claim 5, wherein the ripples are any fluctuations in the energy delivered by the power grid from the expected delivered energy span having time spans less than 30 minutes.

7. The method according to claim 5, wherein the expected delivered energy span is dynamic in time, meaning that it varies over at least one day and night and optionally also over a month and/or a year.

8. The method according to claim 7, wherein the expected delivered energy span being dynamic in time depends on one of or a combination of empiric data of the energy delivered by the power grid seen over the day, month and/or year, an adaptive model predicting the energy delivered by the power grid, and/or the external weather conditions such as temperature, sunshine, cloudiness, barometric state and humidity.

9. The system operating by the method according to claim 1.

10. The method according to claim 5, wherein the ripples are any fluctuations in the energy delivered by the power grid from the expected delivered energy span having time spans less than 15 minutes.

11. The method according to claim 5, wherein the ripples are any fluctuations in the energy delivered by the power grid from the expected delivered energy span having time spans less than 20 minutes.

12. A method of managing, regulating and/or controlling energy consumed by a refrigeration system comprising at least one compressor, a condenser and at least two refrigeration entities in parallel to each other, each refrigeration entity adapted to increase or decrease a physical parameter within a controlled environment, the method comprising:

receiving a message from a controller either to decrease or increase energy consumption so as to provide a short term response to reduce ripples on a power grid;

instructing, by the controller, each refrigeration entity that is in the process of decreasing its physical parameter to stop decreasing its physical parameter when the message is to decrease the energy consumption, while ensuring circulation of refrigerant by the at least one compressor to the extent needed by the refrigeration system; and

instructing, by the controller, each refrigeration entity that is in the process of increasing its physical parameter to start decreasing its physical parameter when the message is to increase the energy consumption, while ensuring circulation of refrigerant by the at least one compressor to the extent needed by the refrigeration system.

13. The method of claim 12, wherein the physical parameter may be a temperature, air humidity, CO₂ concentrations or any other ambient value relevant to the system.

14. The method of claim 12, wherein each refrigeration entity comprises:

a refrigeration entity controller;

a physical parameter probe positioned inside the controlled environment; and

a control valve controlling flow of refrigerant from the at least one compressor to an evaporator for the controlled environment;

wherein the refrigeration entity controller receives an input from the physical parameter probe indicating the physical parameter inside the controlled environment; and

wherein if the physical parameter reaches an upper limit of a range defined by a minimum physical parameter and a maximum physical parameter, the refrigeration entity controller opens the control valve of the associated refrigeration entity;

wherein if the physical parameter reaches a lower limit of the of a range defined by a minimum physical parameter and a maximum physical parameter, the refrigeration entity controller closes the control valve of the associated refrigeration entity.

15. The method of claim 14, wherein the control valve is a solenoid valve.

16. The method according to claim 12, wherein the at least one compressor continues to circulate refrigerant when the controller instructs the refrigeration entities to decrease or increase their physical parameters.

17. The method according to claim 12, wherein the message to decrease energy consumption is provided by the controller when the total energy delivered by the power grid increases above an expected delivered energy span, and the message to increase energy consumption is provided by the controller when the total energy delivered by the power grid decreases below an expected delivered energy span.

18. The method according to claim 12, wherein the at least one compressor is a variable capacity compressor device.