Patent Publication Number: US-2015060557-A1

Title: Energy saving apparatus, system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/980,537, filed Apr. 16, 2014, and is a continuation-in-part of application Ser. No. 14/016,012 filed Aug. 30, 2013, which are hereby incorporated by reference, to the extent that they are not conflicting with the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to Heating Ventilating and Air Conditioning (HVAC) systems, and more particularly to an apparatus, system and method for saving energy during use of HVAC systems, by manipulating the HVAC systems&#39; fan run time and/or compressor run time. 
     2. Description of the Related Art 
     Conventional HVAC systems include temperature changing components for changing the temperature and condition of air. Indoor air handler unit drives air from the temperature changing component through supply ducts to zones within a building. A typical HVAC consists of heating unit, air conditioning unit and the ventilation fan or blower at the air handler unit. A thermostat is used to control the conditions of the air in a conditioned space by sending 24 VAC (Volts Alternating Current) control signals to controllers that activate or deactivate one or more components such as the blower or ventilation fan, furnace, heat exchanger, air conditioning compressor and cooling coil. 
     Conventional HVAC fan controller typically operates the ventilation fan for 0 second to 90 seconds after the furnace or air conditioning compressor has been turned off. 
     Studies have shown that even after the 90 seconds duration, the furnace heat exchanger surface still have residual heat energy left, and the air conditioner cooling coil still has residual cool energy left. This wasted energy is not delivered to the conditioned space when the ventilation fan stops blowing. 
     Therefore there is a need for an apparatus, system and method that can be used to recover additional heating and cooling capacity and to operate HVAC equipment with higher efficiency. 
     Further, in humid and hot areas, the air conditioning compressor can run continuously trying to cool the conditioned space to the set temperature. When the compressor runs continuously, the cooling coil will have water condensing in its cooling coils. 
     Therefore, there is a need for an apparatus, system and method that can shut off the compressor for a short period after the compressor has run continuously for a long period of time, and let the ventilation fan blow the air across the wet cooling coil, such that the condensed water on the cooling coil will evaporate, and thus, provide additional cooling while saving the energy used to run the compressor. 
     The problems and the associated solutions presented in this section could be or could have been pursued, but they are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches presented in this section qualify as prior art merely by virtue of their presence in this section of the application. 
     BRIEF SUMMARY OF THE INVENTION 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
     In an exemplary embodiment, an energy savings apparatus for reducing the energy consumption of Heating Ventilating and Air Conditioning (HVAC) systems is provided. This is accomplished by extending the fan run time of an HVAC system after the heating or cooling unit has shut off and/or shut off the compressor for a short period if it runs continuously for a long period of time. Thus, an advantage is the saving of energy during the operation of HVAC systems. 
     The above embodiments and advantages, as well as other embodiments and advantages, will become apparent from the ensuing description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For exemplification purposes, and not for limitation purposes, embodiments of the invention are illustrated in the figures of the accompanying drawings, in which: 
         FIG. 1  illustrates a diagram of a system for saving energy during operation of an HVAC, according to an embodiment. 
         FIG. 2  is a flow chart depicting a process for saving energy during the heating cycle of an HVAC, according to an embodiment. 
         FIG. 3  is a flow chart depicting a process for saving energy during the cooling cycle of an HVAC, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     What follows is a detailed description of the preferred embodiments of the invention in which the invention may be practiced. Reference will be made to the attached drawings, and the information included in the drawings is part of this detailed description. The specific preferred embodiments of the invention, which will be described herein, are presented for exemplification purposes, and not for limitation purposes. It should be understood that structural and/or logical modifications could be made by someone of ordinary skills in the art without departing from the scope of the invention. Therefore, the scope of the invention is defined by the accompanying claims and their equivalents. 
     Reference will now be made to  FIG. 1  and  FIG. 2 . Again,  FIG. 1  illustrates a diagram of a system for saving energy during operation of an HVAC, according to an embodiment.  FIG. 2  is a flow chart depicting a process for saving energy during the heating cycle of an HVAC, according to an embodiment. 
     As shown in  FIG. 1 , the energy saving system disclosed herein may include a conventional HVAC air handler unit  100 , a temperature probe  103  and an energy saving unit (ESU)  101 . As typical, the air handling unit  100  may include a blower or fan  107 , which through a network of air ducts (not shown), pulls the return air  108  from the heated/conditioned space (e.g., house, office building, etc) and pushes it through the furnace heat exchanger  106  and evaporator coil  105  to obtain the heated/conditioned supply air  104 , which is then pushed further into the heated/conditioned space. 
     As it is well known in the art, the air handler unit  100  may be placed in, for example, the basement or the attic of a house. 
     As shown in  FIG. 1 , the temperature probe  103  is preferably inserted downwind from the cooling coil  105  and the heat exchanger  106 , inside the air duct (not shown) of the supply air  104 , inside the air handler unit air exit. As the air blows across the heat exchanger  106  and the cooling coils  105  inside the air handler unit  100 , the temperature of the heated/conditioned supply air  104 , downwind from the heat exchanger and cooling coil, gives a good indication of their temperature. 
     The energy saving unit (ESU)  101  may be a computer, an improved thermostat, or a combination thereof, having, besides the conventional elements of a thermostat (i.e., temperature probe(s), circuitry, user interface, display, etc; (not shown)), an energy saving module (ESM)  102 . The ESM  102  may include hardware (e.g., circuit board(s), processor(s), memory, etc) and/or logic configured to enable the ESU  101  to perform the energy saving functions described hereinafter. The structural and functional configuration of the ESM will be apparent to one of ordinary skills in the art from the ensuing description of the energy saving processes disclosed herein. 
     The temperature sensed by the temperature probe  103  may be sent to the ESU  101  using for example wireless RF signal(s), or, as another example, using any unused spare wire going from the air handler&#39;s  100  PCB (Printed Circuit Board; not shown) to the ESU  101 , or, yet as another example, sent as high frequency digital signal piggyback on the 24VAC 60 Hz common wire. 
     In a conventional HVAC heating cycle, there is typically a difference between the temperature of the heated supply air  104  and the air temperature sensed by the conventional thermostat in the heated room, after the furnace is turned off. Most furnace heat exchangers are still hot (above 135 to 210° F.) after the furnace fan turns off. The apparatus and process described below, recovers the remaining heat energy from the hot furnace heat exchanger after the furnace turns off and delivers this heat to the heated space. 
     With the use of ESU  101 , this temperature difference can be used to keep the blower fan  107  to continue to run until the downwind probe&#39;s  103  temperature equals the temperature of the heated room. Once this is reached, all the left over energy in the air ducting and at the heat exchanger  106  have been utilized and the blower fan  107  is then shut off. 
     As described in more details below, the ESU  101  adjusts the additional fan operation automatically by monitoring the temperature probe  103  and the temperature in the heated room. It should be apparent that the amount of time the fan continues to operate after the furnace is turned off is directly related to the temperature difference between the supply air  104  measured by probe  103  and the temperature of the air inside the heated room. In the same time, the amount of additional fan run time is an indication of how much left over heat stored in the heat exchanger was saved. 
     Hence, the ESU recovers and delivers more heating energy to the heated space than it is possible with conventional HVAC fan controllers. The ESU improves the efficiency of HVAC equipment by delivering additional heating capacity for a small amount of additional electric energy (kWh) to keep the blower or ventilation fan running. 
     The process of energy saving using the ESU  101  and its ESM  102  in a heating cycle, as shown in  FIG. 2 , may start by turning the ESU on (Step s 21 ) and setting the desired room temperature (Step s 22 ). Upon starting of the ESU  101  for example, the ESM  102  may be configured to start to monitor (Step s 23 ) the temperature of the supply air  104  ( FIG. 1 ), by communicating with the temperature probe  103 . 
     After the set temperature is reached (Step s 24 ), the heater is preferable shut off (Step s 25 ), and the fan  107  ( FIG. 1 ), is kept running for as long as the measured room temperature is smaller than the temperature of the supply air  104  (Steps s 27 - 29 ) at the exit of Air Handler  101  ( FIG. 1 ). Preferably, the ESM  102  may be configured to compare (Step s 27 ) the temperature of the supply air  104  with the measured room temperature after a preset period (e.g., 30 seconds) after the heater was turned off. Alternatively, the comparison may be done continuously or periodically (e.g., every 10 seconds) after the heater was shut off. 
     The fan  107  is preferably stopped (Step s 210 ) when the measured room temperature equals the temperature of the supply air  104 . It should be observed that the set room temperature and the measured room temperature are the same when the heater is stopped and the additional/extended, energy saving running period of the fan begins. 
     As shown in  FIG. 2 , the heater and fan keep running (Step s 26 ) until the measured room temperature equals the set room temperature, and, the cycle is repeated every time the measured room temperature falls below the set room temperature. 
       FIG. 3  is a flow chart depicting a process for saving energy during the cooling cycle of an HVAC, according to an embodiment. 
     The process of energy saving using the ESU  101  and its ESM  102  in a cooling cycle, as shown in  FIG. 3 , may start by turning the ESU on (Step s 31 ) and setting the desired room temperature (Step s 32 ). For example, upon starting of the ESU  101 , the ESM  102  may be configured to start to monitor (Step s 33 ) the temperature of the supply air  104  ( FIG. 1 ), by communicating with the temperature probe  103 . 
     After the set temperature is reached (Step s 34 ), the compressor (not shown) is preferable shut off (Step s 35 ), and the fan  107  ( FIG. 1 ), is kept running for as long as the measured room temperature is greater than the temperature of the supply air  104  (Steps s 37 , s 39 , s 312 ). 
     The fan  107  is preferably stopped (Step s 311 ) when the measured room temperature equals the temperature of the supply air  104 . It should be observed that the set room temperature and the measured room temperature are the same when the compressor is stopped and the extended, energy saving running period of the fan begins. 
     Preferably, the ESM  102  may be configured to compare (Step s 37 ) the temperature of the supply air  104  with the measured room temperature after a preset period (e.g., 30 seconds) after the compressor was turned off. Alternatively, the comparison may be done continuously or periodically (e.g., every 10 seconds) after the compressor was shut off. 
     As shown in  FIG. 3 , the compressor and fan keep running (Step s 36 ) until the measured room temperature equals the set room temperature, and, the cycle is repeated every time the measured room temperature rises above the set room temperature. 
     As known in the art, air conditioners cool conditioned spaces by removing sensible and latent heat from the return air  108  ( FIG. 1 ), which reduces the supply air&#39;s  104  temperature and humidity. Latent heat is removed as water vapor is condensed out of the air due to the temperature of the cooling coil  105  being less than the return air&#39;s  108  dew point temperature. 
     Latent heat is the quantity of heat absorbed or released by air undergoing a change of state, such as water vapor condensing out of the air as water onto a cold cooling coil or cold water evaporating to water vapor which will cool the air. 
     In a conventional HVAC operation most cooling coils are cold (below 40 to 50° F.) and wet after the compressor turns off. Cooling energy left on the cooling coil after the compressor turns off is generally wasted. The cooling coil absorbs heat from the attic and cold water on the coil flows down the condensate drain. The apparatus and process disclosed herein recovers the remaining cooling energy from the cooling coil  105  by operating the fan  107  after the compressor turns off, to cool the conditioned space. By using the data from a humidity sensor  109  ( FIG. 1 ) installed in the ESU  101 , measuring how long the compressor has been running, and sensing the temperature of the probe  103  inserted downwind at the air duct in the air handler unit  100 , the compressor can be programmed to shut down for a short, adjustable period of time (e.g., 3, 4, or 5 minutes, etc), while the fan  107  keeps running. When this happens, the condensed water on the cooling coil will be evaporated away. While saving the energy used to run the compressor, this will provide additional cooling and will also provide additional moisture to the air in the room, by pushing the resulting water vapors through the air ducts into the room, thus helping keep the humidity level at more desirable levels. Moisture in the air helps for example those with sinus problems breathe better, and also helps those with sensitive skins. 
     Therefore, there is a need for an apparatus, system and method that can shut off the compressor for a short period after the compressor has run continuously for a long period of time to let the ventilation fan blow the air across the wet cooling coil. By doing so, the air blowing across the cooling coil will extract the cooling latent energy from the water evaporating from the cooling coil surfaces before the set temperature is reached. 
     The apparatus disclosed herein (i.e., ESU  101 ) works by manipulating multiple sets of data to achieve higher energy efficiency, than by using the regular, conventional thermostat. Preferably, there are four (4) sets of data: 1) the conditioned room temperature as sensed by the ESU  101 ; 2) the duration the compressor has been running continuously as measured by the ESU  101 ; 3) the humidity of the air in the conditioned room as sensed by a moisture sensor  109  in the ESU  101 ; and 4) the temperature downwind of the cooling coil and heat exchanger as sensed by a probe  103  inserted inside the air handler air duct. 
     The software and hardware in the ESM  102  of the ESU  101  may monitor, calculate and/or compare these 4(four) sets of data preferably continuously, and sends out the appropriate, for example, 24 VAC signals using the regular colored wires to the HVAC control boards, typically located at the air handler unit  100 . 
     As shown in  FIG. 3 , before the set temperature is reached (Step s 34 ) and before the compressor run duration is reached (Step s 38 ), the compressor keeps running (Step s 36 ). The compressor run duration can be calculated by the ESM  102  and/or set/adjusted by a user to for example any duration between 15 and 30 minute based on factors such as the tonnage of the air conditioner compressor, size of the conditioned space, geographical location of the installation (e.g., dry climate versus humid climate, etc), user desired humidity level inside the conditioned space, and so on. 
     When the compressor&#39;s run duration is reached, the humidity of the air in the conditioned room as sensed by a moisture sensor  109  is checked (Step s 310 ), and if (Step s 313 ) the humidity level is below a set level (e.g., 45%), the compressor is stopped (Step s 314 ) and the fan  107  is kept running, assuming of course that the measured room temperature is greater than the temperature of the supply air  104 , which will typically be the case. The compressor may be stopped for a short period of time (e.g., 3, 4, or 5 minutes), calculated by the ESM  102  and/or set/adjusted by a user after which the compressor restarts (Steps s 315 - 316 ). The air conditioning compressor shutdown duration may be based on the sensed humidity, supply air temperature, conditioned room temperature and the duration the compressor has been continuously running. For example, if the sensed humidity is say 40%, supply air temperature and conditioned room temperature delta is 3 deg F., and compressor has been running non-stop for 30 minutes, then the algorithm will calculate the compressor shut off duration to be for example 25 minutes. The ESM  102  can be programmed by the user by inputting the desired fixed shut off period or by inputting a set of desired humidity and temperature levels for example, and let the computer calculate the compressor shut off duration. 
     The humidity level may be set, typically based on user&#39;s instructions, and based for example on the sensitivity of the occupants of the conditioned space to dry air and may be adjusted by the user/occupants. 
     Thus, the apparatus and process disclosed herein, saves energy by extending the fan  107  run time to make use of latent energy from water evaporating from the evaporator coil  105 . When the air conditioner evaporative coil  105  gets cold, water condenses onto the coil. So, the compressor can be shut down for a few minutes, but with the air still flowing across the coil  105 . This will evaporate the water on the coil and supply the resulting cooling energy to the conditioned space. 
     Hence, the apparatus and the respective processes disclosed for the heating and cooling cycle recovers and delivers more heating and cooling energy to the conditioned space than it is possible with conventional HVAC thermostat. The apparatus and the processes disclosed improve the efficiency of the HVAC equipment by delivering additional heating or cooling capacity for a small amount of additional electric energy (Kwh) to keep the blower or ventilation fan running. 
     Therefore, the energy savings apparatus, system and processes disclosed herein reduce the energy consumption of typical HVAC systems. 
     Alternatively or in parallel, instead of using the temperature probe  103  inserted downwind after the cooling coil and heat exchanger, a timing algorithm can be used to estimate the amount of cool or heat energy left in these elements based on how long the compressor has been running, how long the heater has been running and/or the humidity of the conditioned room. The ESU can be programmed to let the additional fan run time based on this data. This will eliminate the use of the temperature probe. While this method may not be as accurate as inserting a temperature probe at the air handler unit air duct, there are installation cost savings. 
     It may be advantageous to set forth definitions of certain words and phrases used in this patent document. 
     “Logic” as used herein and throughout this disclosure, refers to any information having the form of instruction signals and/or data that may be applied to direct the operation of a processor. Logic may be formed from signals stored in a device memory. Software is one example of such logic. Logic may also be comprised by digital and/or analog hardware circuits, for example, hardware circuits comprising logical AND, OR, XOR, NAND, NOR, and other logical operations. Logic may be formed from combinations of software and hardware. 
     The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. 
     As used in this application, “plurality” means two or more. A “set” of items may include one or more of such items. Whether in the written description or the claims, the terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of,” respectively, are closed or semi-closed transitional phrases with respect to claims 
     Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. With regard to flowcharts, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the described methods. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments. 
     One embodiment of the invention may be described as a process which is usually depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed. A process may correspond to a method, a program, a procedure, a method of manufacturing or fabrication, etc. 
     Although specific embodiments have been illustrated and described herein for the purpose of disclosing the preferred embodiments, someone of ordinary skills in the art will easily detect alternate embodiments and/or equivalent variations, which may be capable of achieving the same results, and which may be substituted for the specific embodiments illustrated and described herein without departing from the scope of the invention. Therefore, the scope of this application is intended to cover alternate embodiments and/or equivalent variations of the specific embodiments illustrated and/or described herein. Hence, the scope of the invention is defined by the accompanying claims and their equivalents. Furthermore, each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the invention.