Retrofit HVAC attached energy storage system and process
The invention described herein represents a significant improvement in the efficiency of cooling processes for applications such as buildings, computer equipment, processes, and refrigeration. Described is HVAC energy attached storage whereby an existing HVAC systems cooling capacity is augmented by the addition of a phase changed compressed refrigerant storage and control system. Energy is stored at a first time for subsequent use when electricity is more expensive than a threshold, when electricity availability is constrained, when the thermal load to be cooled is forecasted to be above a threshold, or when a renewable energy source is less available than a threshold.
This invention is a Continuation In Part of U.S. patent application Ser. No. 12/217,575 filed on Jul. 7, 2008, of U.S. patent application Ser. No. 12/586,784 filed on Sep. 26, 2009, and of U.S. patent application No. 12/653,521 filed on Dec. 15, 2009.
BACKGROUND1. Field of Invention
This invention relates to heat pumps used in heating and cooling a wide range of applications such as in buildings, data centers, refrigeration, equipment, or industrial processes for example. More specifically, this invention relates to methods to store energy in the form of a phase changed refrigerant.
2. Description of Prior Invention
Heat pumps are well known and have been used for heating and cooling applications for more than 100 years. As practiced today, heat pumps use a full refrigeration cycle that comprises both a compression component and an expansion component. The present invention describes integrated heating, cooling, energy transformation and energy storage elements whereby the compression and the expansion aspects are separately controlled and operated non-concurrently.
BRIEF SUMMARYThe present invention is drawn to augmenting the performance of an existing chiller by integrating therewith HVAC attached energy storage and non-concurrent compression/condensation and evaporation process steps. The system stores energy as a phase changed fluid which is then employed to augment the operation of an existing chiller or other climate control system.
OBJECTS AND ADVANTAGESAccordingly, several objects and advantages of the present invention are apparent. It is an object of the present invention to provide energy efficient heating processes. It is an object of the present invention to provide an energy efficient cooling process. It is an object of the present invention to store energy in a phase changed state for subsequent use in passive heating or cooling applications. It is an object of the present invention to provide these advantages as a retrofitted add on to an existing thermal transfer system.
Further objects and advantages will become apparent from the enclosed figures and specifications.
Many buildings have existing thermal control systems for heating and cooling buildings and processes and equipment therein, such systems lasting decades and being very expensive to replace. To shift energy use loads off peak or to when additional energy is needed for heating or cooling it is beneficial to install a secondary retrofit system to augment the capacity of the existing system. Using HVAC attached energy storage as described herein, a small Retrofit Storage HVAC System can easily be installed to interface with the secondary fluid loop of the existing chiller 21. A non-concurrent heat pump 29 comprises the means to compress refrigerant at a first time and to evaporate that refrigerant at a second time as has been described in the applicant's prior applications cited in the related applications section of this document and included herein by reference.
Integration of the Retrofit Storage HVAC System with the existing chiller 21 is simple because it comprises cutting into the return thermal exchange fluid 23 pipe to install a return fluid valve 47 and cutting into the chilled thermal exchange fluid 25 pipe to install a chilled fluid valve 49. Depending upon configuration, distances, and system sizes, one or more fluid pumps (not shown) may also be added to ensure proper fluid flow to and from each of the existing chiller 21 and the non-concurrent heat pump 29.
A refrigerant gas tank 31 is provided to house a refrigerant in its gas state. If ammonia is to be used as the refrigerant, its pressure will be around 50 psi and the tank's UL listed pressure will be 250 psi. If the system is to store 1 million BTUs of cooling capacity, the refrigerant gas tank 31 will have a capacity of approximately 2500 gallons. Software in a control system (not shown) dictates when the compression side of the system is to run and at a first time opens a gas tank valve 33 which allows refrigerant gas to be drawn to a compressor 35 which is driven by a motor to perform compression work on the gas which is then passed to a condenser 37 where heat is dumped and the refrigerant becomes a liquid. A liquid tank valve 39 is opened by the software/control system (not shown) to enable the liquid refrigerant to be directed into a refrigerant liquid tank 41. Note that the applicant's prior patent applications cited and referenced herein and included by reference describe software, control, and alternate storage tank mechanisms suitable for use herein. If ammonia is to be used as the refrigerant, its liquid pressure will be around 170 psi and the tank's UL listed pressure will be 250 psi, and if the system is to store 1 million BTUs of cooling capacity, the refrigerant liquid tank 41 will have a capacity of approximately 500 gallons. (Ammonia is given as an example, any refrigerant is suitable for use in the art described herein.) The gas tank valve 33 and the liquid tank valve 39 each have a single port for accessing their respective tanks and two pipe ports so that they can be operated by solenoid to be in any one of four states including 1) closed, 2) open to the compression loop, 3) open to the evaporation loop, or 4) open to both the compression loop and the evaporation loop. While a single valve is shown for gas tank valve 33 and another for the liquid tank valve 39, in practice as later described a series of valves may be the flow control directing mechanism needed to controllably achieve the 4 desired flow states.
At a second time the liquid tank valve 39 is opened such that liquid refrigerant is directed to a throttling valve 43 which controllably directs its flow to an evaporator 45 where the liquid refrigerant is evaporated to become a gas refrigerant thereby providing a cooling thermal energy transfer function before being direct through the gas tank valve 33 into the refrigerant gas tank 31. The evaporator 45 is the main interface of the non-concurrent heat pump 29 with the thermal load 27 via the existing chiller 21 secondary fluid loop and return fluid valve 47 and chilled fluid valve 49 that have been installed as the common interface between the thermal load 27 and the existing chiller 21 and the retrofitted non-concurrent heat pump 29.
Both the return fluid valve 47 and the chilled fluid valve 49 are solenoid controlled to direct flow in 3 settings. Both always direct flow to/from the thermal load and have three settings including 1) open to the existing chiller 21, 2) open to the non-concurrent heat pump 29, and 3) open to both the existing chiller 21 the non-concurrent heat pump 29. While a single valve is depicted for return fluid valve 47 and another for the chilled fluid valve 49, in practice a series of valves may be needed to controllably achieve the three return fluid valve 47 and the chilled fluid valve 49 desired states. Thus three possible cooling capacities can be applied to the thermal load 27. First the existing chiller 21 can operate independently to cool the thermal load 27. Secondly the non-concurrent heap pump 29 can operate independently to apply its stored capacity to cool the thermal load 27. (Note it is also possible that the non-concurrent heat pump 29 can operate the compressor 35 and evaporators 45 concurrently.) Thirdly, the existing chiller 21 can operate to cool the thermal load while simultaneously the non-concurrent heap pump 29 cooperates to apply its stored capacity to cool the thermal load 27.
A fluid interface is defined as comprising the means to transfer thermal energy from the thermal load 27 via the thermal transfer fluid pipes and thermal energy transfer fluid therein where thermal energy is absorbed by an element in the non-concurrent heat pump 29 and its evaporator 45. Examples of thermal energy transfer fluid include air, H2O, and glycol.
While the existing chiller 21 operates on a concurrent cycle, that is to say the compressor and evaporator are both processing equal masses of refrigerant concurrently, the non-concurrent heat pump 29 operates the compressor 35 at a first time as a means to drive energy storage into the refrigerant liquid tank 41 for a subsequent non-concurrent time. At a second time, the compressed refrigerant is evaporated in the evaporator 45 and thereby absorbing thermal energy from the secondary fluid loop which carries the thermal energy from the thermal load 27.
Thus in the retrofit non-concurrent heat pump 29, refrigerant compressed at a first time, generally off peak, is stored energy in the form of a compressed refrigerant stored capacity to cool. Off peak energy can be purchased more cheaply and also cooler ambient weather conditions, such as at night, can more efficiently absorb thermal energy from the compressor 35 and condenser 37 during the refrigerant compression part of the non-concurrent cycle. At a second time, the compressed refrigerant is evaporated to cool the thermal load 27. The second time may be when energy is more expensive or when the thermal load 27 is too great for the existing chiller 21 to handle unassisted, or when the existing chiller has power restrictions due to power outage or staged shut down by excess utilization on the electric grid. Thus electric energy, wind energy, or solar energy are used during abundant, cheap, and more efficient times for later use during peak, scarce, expensive, and less efficient times.
For component sizing, if the non-concurrent heat pump 29 system is to build up a compressed refrigerant charge daily, for example over 16 hours and the compressed refrigerant charge is to be released daily over a shorter time, for example during a peak 8 hours, the compressor 35, its driving motor, and the condenser 37 can have smaller thermal energy transfer capacities compared to the evaporator 45. Similarly, if the compressed refrigerant charge is to be used only on rare occasions in an emergency back up situation, the compressor 35, its driving motor and the condenser 37 can possess perhaps 5% the thermal energy transfer capacity of those in the existing chiller 21 while the evaporator 45 may be the same thermal transfer capacity as that in the existing chiller 21. The compression cycle of such a system will run over the course of a week or more to fully charge the refrigerant liquid storage tank 41 which may then discharge its entire stored cooling capacity over the course of a few hours or a day. Such retrofit systems can be significantly cheaper than is the existing chiller 21 while providing valuable options to ensure proper cooling of the thermal load 27 during many cost savings, energy savings, and emergency backup scenarios.
Valves described herein comprising a mechanism to controllably direct flow.
SECOND EMBODIMENTIn any refrigerant flow directions or fluid flow directions depicted or described herein, back check valves (not shown) may be added to ensure flow is only in the desired direction and can not go backwards. Also in any refrigerant flow directions or fluid flow directions depicted or described herein, sensors (not shown) may be added to sense flow volumes and direction to be utilized as a process input for calculating optimal performance whereby valves can be opened or closed or the compressor or throttle valve can be accelerated or decelerated to ensure optimal performance and safety. Each directing valve depicted or described herein is a flow control or flow directing mechanism. Where the valve is to direct flow between two or more pipes, a valve comprising the desired number of input orifices and the desired number of output orifices can be used or multiple three way valves can be used in series where an input can be controllably directed to a capped (dead end) output, to another three way valve output, or to a desired component in the system output. In series, a multitude of three way valves effectively can control the output directions to any number of pipes. This and other valve arrangements are possible to comprise the flow control mechanism. It should be noted that fluid pumps may be added to any refrigerant pipes or heat transfer fluid pipes described or depicted herein to optimize system performance. In
Control mechanism are discussed in the related applications cited at the top of this application and included herein by reference but not described herein to avoid redundancy. Control to elements include a microcontroller with inputs, outputs, control logic, and memory. The related applications describe scenarios and logic to determine when to compress and store refrigerant in a first operating mode and when to evaporate refrigerant to cool a thermal load in a second operating mode. Thus controlling logic is provided to determine and control when each operational mode runs such that during a time when electricity is cheaper than a threshold, or electricity is forecasted to be abundantly available, or when the thermal load to be cooled is forecasted to be below a threshold, or when a renewable energy source is more available, the controlling logic and microcontroller will operate the first mode. Similarly, the controlling logic and microcontroller will operate the second mode when electricity is more expensive than a threshold, or when electricity availability is constrained, or when the thermal load to be cooled is forecasted to be above a threshold, or when a renewable energy source is less available than a threshold.
OPERATION OF THE INVENTIONOperation of the invention has been discussed under the above heading and is not repeated here to avoid redundancy.
CONCLUSION, RAMIFICATIONS, AND SCOPEThus the reader will see that the apparatus and processes of this invention provides an efficient, energy saving, greenhouse gas reducing, thermal pollution reducing, novel, unanticipated, highly functional and reliable means for heating and cooling buildings and equipment and processes therein.
As has been described by the related applications cited and included herein by reference, the refrigerant gas tank can be replaced by a naturally occurring gas storage mechanism such as the Earth's atmosphere wherein the refrigerant is a gas extracted from the Earth's atmosphere (such as air, oxygen, nitrogen, CO2 for example), compressed to a liquid by the compressor herein and stored in the refrigerant liquid storage tank, then utilized to perform the cooling thermal energy transfer function in the evaporator herein then release back to the atmosphere. The atmosphere being a low pressure refrigerant storage means equivalent to the refrigerant gas tank herein.
Intervening Components Valves, Pumps, SensorsWhile the above description describes many specifications, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of a preferred embodiment thereof. Many other variations are possible.
Claims
1. A thermal energy transfer process comprising;
- providing a refrigerant compressor,
- providing a liquid refrigerant flow control mechanism,
- providing a liquid refrigerant storage tank,
- providing a refrigerant evaporator,
- providing a gas refrigerant flow control mechanism,
- providing a gas refrigerant storage tank,
- providing a refrigerant,
- wherein said refrigerant is controllably directed through the following steps, at a first time said liquid refrigerant flow control mechanism controllably directs liquid refrigerant flow to be from said refrigerant compressor to said refrigerant evaporator, and said gas refrigerant flow control mechanism controllably directs gas refrigerant flow to be from said refrigerant evaporator to said refrigerant compressor, at a second time said gas refrigerant flow control mechanism controllably directs gas refrigerant flow to be from said gas refrigerant storage tank to said refrigerant compressor, and said liquid refrigerant flow control mechanism controllably directs liquid refrigerant flow to be from said refrigerant compressor to said liquid refrigerant storage tank, and at a third time said liquid refrigerant flow control mechanism controllably directs liquid refrigerant flow to be from said liquid refrigerant storage tank to said refrigerant evaporator, and said gas refrigerant flow control mechanism controllably directs gas refrigerant flow to be from said refrigerant evaporator to said gas refrigerant storage tank.
2. The thermal energy transfer process of claim 1 wherein a throttling valve is provided to control the refrigerant flow between the liquid refrigerant flow control mechanism and the refrigerant evaporator.
3. The thermal energy transfer process of claim 1 wherein a condenser is provided between the refrigerant compressor and the liquid refrigerant flow control mechanism.
4. The thermal energy transfer process of claim 1 wherein a thermal energy absorbed at said refrigerant evaporator is used to cool a thermal load.
5. The thermal energy transfer process of claim 1 wherein a fluid is provided to transfer thermal energy from the thermal load to the refrigerant evaporator.
6. The thermal energy transfer process of claim 5 wherein said thermal load comprises heat from one selected from the group consisting; from a building, from a refrigerated space, from a process that generates heat, and from equipment that generates heat.
7. The thermal energy transfer process of claim 1 wherein said liquid refrigerant flow control mechanism is one selected from the group consisting of a single valve, and multiple valves.
8. The thermal energy transfer process of claim 1 wherein said gas refrigerant flow control mechanism is one selected from the group consisting of a single valve, and multiple valves.
9. The thermal energy transfer process of claim 1 wherein
- at a forth time said liquid refrigerant flow control mechanism controllably directs liquid refrigerant flow to be from said refrigerant compressor to said refrigerant evaporator, and said gas refrigerant flow control mechanism controllably directs gas refrigerant flow to be from said refrigerant evaporator to said refrigerant compressor,
- and said liquid refrigerant flow control mechanism controllably directs liquid refrigerant flow to be from said liquid refrigerant storage tank to said refrigerant evaporator, and said gas refrigerant flow control mechanism controllably directs gas refrigerant flow to be from said refrigerant evaporator to said gas refrigerant storage tank.
10. The thermal energy transfer process of claim 1 wherein controlling logic is provided to determine and control when each operational mode runs such that said second time comprises one selected from the group consisting of; a time when electricity is cheaper than a threshold, a time when electricity is forecasted to be abundantly available, a time when the thermal load to be cooled is forecasted to be below a threshold, and a time when a renewable energy source is more available than a threshold, and wherein said third time comprises one selected from the group consisting of; a time when electricity is more expensive than a threshold, a time when electricity availability is constrained, a time when the thermal load to be cooled is forecasted to be above a threshold, and a time when a renewable energy source is less available than a threshold.
11. A thermal energy transfer process comprising;
- providing a first thermal climate control means.
- providing a fluid interface,
- providing a thermal load to be cooled
- providing a second thermal climate control means comprising; providing a refrigerant compressor providing a refrigerant evaporator providing a liquid refrigerant storage tank providing a gas refrigerant storage tank, providing a refrigerant
- and in a first operational mode said refrigerant compressor receives gas refrigerant from said gas refrigerant storage tank, compresses said gas refrigerant to become a liquid refrigerant, and said liquid refrigerant is deposited in said liquid refrigerant storage tank, wherein said liquid refrigerant is stored for subsequent evaporation,
- and in a second operational mode said refrigerant evaporator receives said liquid refrigerant from said liquid refrigerant storage tank, evaporates said liquid refrigerant to become a gas refrigerant thereby absorbing thermal energy from said fluid interface to cool said thermal load, and said gas refrigerant is deposited in said gas refrigerant storage tank, wherein said gas refrigerant is stored for subsequent compression,
- and in a third operational mode the first thermal climate control means absorbs thermal energy from said fluid interface to cool said thermal load,
- And wherein cooling capacity is applied to the thermal load in a combination from the group consisting of; the third mode cools without the second mode, the second mode cools without the third mode, both the second mode and third mode cool concurrently.
12. The thermal energy transfer process of claim 11 wherein controlling logic is provided to determine and control when each operational mode runs such that
- said first operational mode is controlled to run under a condition selected from the group consisting of; when electricity is cheaper than a threshold, when electricity is forecasted to be abundantly available, when the thermal load to be cooled is forecasted to be below a threshold, and when a renewable energy source is more available than a threshold,
- and said second operational mode is controlled to run under a condition selected from the group consisting of when electricity is more expensive than a threshold, when electricity availability is constrained, when the thermal load to be cooled is forecasted to be above a threshold, and when a renewable energy source is less available than a threshold.
13. The thermal energy transfer process of claim 11 wherein, to said second thermal climate control means, a throttling valve is provided to control the refrigerant flow between the liquid refrigerant flow control mechanism and the refrigerant evaporator.
14. The thermal energy transfer process of claim 11 wherein, to said second thermal climate control means, a condenser is provided between the refrigerant compressor and the liquid refrigerant flow control mechanism.
15. The thermal energy transfer process of claim 11 wherein said fluid interface comprises a heat transfer fluid to transport thermal energy from the thermal load to said evaporator in said second operational mode and to said first thermal climate control means in said third operational mode.
16. The thermal energy transfer process of claim 15 wherein said heat transfer fluid is selected from the group consisting of, H2O, glycol, and air.
17. The thermal energy transfer process of claim 15 wherein in said second operational mode said heat transfer fluid is controllably directed to dump thermal load into said evaporator, and in said third operational mode said heat transfer fluid is controllably directed to dump thermal load into said first thermal climate control means.
18. The thermal energy transfer process of claim 17 wherein said heat transfer fluid is controllably directed by a flow control mechanism selected from the group consisting of, a single valve, and multiple valves.
19. The thermal energy transfer process of claim 11 wherein said thermal load comprises heat from one selected from the group consisting; from a building, from a refrigerated space, from a process that generates heat, and from equipment that generates heat.
20. The thermal energy transfer process of claim 11 wherein a flow control mechanism directs refrigerant flow to and from said liquid refrigerant storage tank whereby
- in said first operational mode liquid refrigerant is directed to flow into said liquid refrigerant storage tank and blocked from flowing into said refrigerant evaporator,
- and in said second operational mode liquid refrigerant is directed to flow into said refrigerant evaporator and blocked from flowing to said refrigerant compressor.
Type: Application
Filed: Apr 16, 2010
Publication Date: Oct 14, 2010
Inventor: Ray M. Alden (Raleigh, NC)
Application Number: 12/799,103
International Classification: F25D 23/00 (20060101);