EA043362B1 - METHOD FOR CONTROLLING TEMPERATURE IN THE SPACE INSIDE A BUILDING - Google Patents

Description

Cross references to related applications

This regular patent application claims priority to a previously filed provisional application. The provisional application names the same inventor. It was filed on August 26, 2019 and was assigned Serial No. 62/891581.

Statement Concerning Federally Supported Research or Development

Not applicable.

Microfilm application

Inapplicable item.

Field of technology

This invention relates to the field of heating, ventilation and air conditioning. More specifically, the invention provides a new system in which local cooling micro-heat exchangers are used instead of a centralized heating and cooling unit.

State of the art

The present invention can be used in buildings of various sizes and configurations. Commercial structures will be a common application and the reader will benefit from a brief description of existing systems used for such buildings. The reader should keep in mind that there are many different types of systems in use today. The following explanation applies only to one exemplary prior art system. However, it will properly serve as a basic understanding of the prior art and will help the reader understand the advantages of the present invention.

In fig. 1 shows a multi-story building 10. Heating, ventilation and air conditioning (HVAC) is provided by large centralized units. The installation 14 in the form of a cooling micro-heat exchanger and the hot water installation 16 are located on the roof or in large underground equipment rooms. The installation, in the form of a cooling heat exchanger, cools the water, which is then circulated throughout the building, providing the necessary cooling. Heat is removed from the installation in the form of a cooling heat exchanger through a cooling tower 24 located on the roof. The chilled water circulates through a closed cold water circuit (not shown in Fig. 1).

The hot water unit 16 heats the water, which is then circulated throughout the building in a closed hot water loop. The closed hot water circuit is separated from the closed cold water circuit. Each floor 12 contains one or more air treatment chambers 18. An air duct system 20 extends from each air treatment chamber 18 . Cold water is supplied to each air treatment chamber 18 through a closed cold water circuit, and hot water is supplied to each air treatment chamber through a closed hot water circuit. Some systems mix hot and cold water near or inside the air handling chamber. Other systems have a separate hot water coil and cold water coil inside each air handler, leaving the hot and cold water supplies separate.

The temperatures required for the hot and cold water circuits in the example in FIG. 1 are dictated by the maximum possible cooling and heating loads. For example, a closed cold water loop must be cold enough to provide the maximum cooling required for any air handler. For large commercial buildings, it is common to cool the water in a closed cold water loop to approximately 7°C (45°F). This provides sufficient cooling capacity for peak demand that may occur in any air handler in a building. Peak demand occurs quite rarely, and maintaining a closed cold water loop at such a low temperature significantly reduces the overall efficiency of the prior art system.

The water in a closed hot water circuit is usually maintained at around 50-60°C (122-140°F). This temperature provides sufficient performance for the peak heat load of any air handler. In the case of a closed cold water loop, peak demand rarely occurs and maintaining hot water at such an elevated temperature creates inefficiency.

In fig. 2-4 provide additional details regarding the prior art system shown in FIG. 1. In FIG. Figure 2 shows an example configuration for a cooling coil, cooling tower, and closed cold water loop installation. In installations in the form of a cooling heat exchanger, various operating cycles of the heat engine are used. In the example of FIG. 2 uses a compressor based cycle. The cooling microheat exchanger unit 14 is typically a vapor compression refrigeration unit. The power supply 34 supplies electrical power to the compressor and control electronics. The heat engine inside the unit, in the form of a cooling heat exchanger, cools the water circulating in the closed cold water circuit 28 and heats the water circulating in the cooling tower circuit 32.

The circulation pump 26 moves water within a closed cold water circuit 28 through the air treatment chambers 18. If cooling is required, the flow of cold water through a designated air handling chamber is activated and a fan within the air handling chamber moves air through a heat exchanger (coil) through which the cold water is pumped. This interaction cools the air, and the cooled air is then circulated through the attached duct system. Flow control valves are used to control the flow of cold water through any particular air handling chamber. These valves are not shown in FIG. 2.

Pump 30 supplies heated water within cooling tower circuit 32 to cooling tower 24, which in this example is mounted on the roof. The cooling tower may be an open loop evaporative type or a closed loop type. In either case, the heat carried by the water in the cooling tower circuit 32 is transferred to the air, which is drawn through the cooling tower. The cooled water is then returned back to the unit 14 in the form of a cooling heat exchanger.

In fig. 3 shows an exemplary closed hot water loop 40. The hot water unit 16 is often referred to as a boiler, but in this example hot water is circulated as the heating medium (some systems use steam). In the example shown, natural gas is supplied to the unit through gas inlet 36 and exhaust gases are carried away by flue 38. Natural gas is burned to heat water circulating in a closed hot water loop 40. Circulation pump 27 circulates heated water throughout the building.

In this example, each air handling chamber 18 can receive hot water as needed. Flow control valves are used to control the flow of hot water through any particular air handler. As for the cold water example, these valves are not shown in FIG. 3. In some systems, the flow of hot and cold water can be controlled separately through each air handler. Other systems simply turn the flow on or off and regulate heat transfer by adjusting fan speed or water flow delay.

In fig. 4 shows additional details of one air handling chamber 18 on one floor of a building. The main fan 44 forces air through the air handling chamber and over a coil (heat exchanger) that is connected to the hot water loop and a coil that is connected to the cold water loop. Air is supplied to the air treatment chamber from two sources. The first is recirculated air supplied through one or more recirculation units 71. The second air source is air supplied from outside through inlet 46.

The flow of cold water from the cold water loop 28 through the air handler is controlled in this example by control valve 58. The hot water flow from the hot water loop 40 is controlled by control valve 56. The air flow is controlled by air valves 50, 52, 54. The overall control system controls these components. Operating modes and symptoms include the following.

1. Control valves have a limited operating range, so the air handler can be set to the desired temperature by providing full cold water flow and limited hot water flow.

2. The desired fresh air mixture can be provided by operating for a period of time with air valve 52 fully closed and air valves 50 and 54 open. In this mode, recirculation fan 42 is activated to blow recirculated air outward from exhaust 48. Main fan 44 is designed to to suck in outside air through inlet 46.

3. A replaceable filter is provided for intake 46.

4. A mixture of recirculated and fresh air can be distributed through the air distribution duct 74 and supply units 72 by closing the air valve 50 and the air throttling valves 52 and 54.

5. Inlet 46 may be one or more large mains supplying the entire building, rather than one inlet for each air handler or floor.

6. Outlet 48 can be one for the entire building, with all air treatment chambers connected to one outlet.

Of course, most floors in most large buildings will have more than one air handler. In fig. 5 shows a plan view of one floor 70. Thermal loads from solar radiation are typically significant in commercial buildings. On many days, the side of a floor facing the sun will require air conditioning, while the shady side of the same floor may require heating. It is customary to divide the floor, as shown in Fig. 5, for five HVAC zones. These are Central Zone 60, East Zone 62, North Zone 64, West Zone 66 and South Zone 68. Each of these zones typically has a separate air handling chamber.

In fig. Figure 6 shows the same floor plan with the addition of five air handlers and associated ductwork. The air treatment chambers are the central zone air treatment chamber 76, the east zone air treatment chamber 78, the north zone air treatment chamber 80, the west zone air treatment chamber 82, and the south zone air treatment chamber 84. A main air duct with branches runs from each air processing chamber. In this type of system, each air handling chamber is connected to a closed cold water circuit and a closed hot water circuit.

In an exemplary prior art system, each air handling chamber operates independently to provide the desired temperature in its associated area.

Such prior art systems do provide adequate heating and cooling, but they are not very efficient. As explained earlier, the closed cold water loop must be maintained at a temperature low enough to meet the maximum cooling demand for any one air handler. This requires providing water at approximately 7°C (45°F). Such cold water will be rarely required, but must be maintained to meet local peak demand. The same problem exists for a closed hot water circuit, where water at a temperature of approximately 6070°C must be provided, although such a high temperature may only be needed at one or two points in the entire building.

In a typical commercial building, an HVAC installation uses an average of 235 kW of power per 1000 kWh of cooling. This gives a heat transformation coefficient (CTF) of 4.25. When using the most advanced oil-free compression technology, energy consumption can be reduced to 109 kW per 1000 kW/h of cooling (CCT is 9.1).

Most commercial HVAC systems are powered by electricity generated from fossil fuels. Carbon dioxide emissions are now a globally recognized problem. Electricity generation is the largest source of carbon dioxide emissions, with approximately 10,000 metric tons of carbon dioxide released into the environment for every

MWh of electricity generation. Commercial buildings account for the majority of electricity demand, and the largest energy consumer in most commercial buildings is air conditioning.

Air conditioning in most existing commercial buildings is provided by an installation in the form of a cooling heat exchanger. Approximately 80% of all cooling heat exchangers currently sold are used to replace or retrofit existing equipment. The remaining 20% is used for new construction. So, upgradeability is an obvious goal for any new type of HVAC system. In the present invention, it is generally not necessary to replace the air ducts and air handling chamber installations. They can usually be retained with reasonable modifications. The system of the present invention can replace most of all existing commercial HVAC systems.

Thus, the present invention is applicable to both existing buildings and new construction. While prior art systems provide CFCs between 4.0 and 9.1, the present invention can provide CFCs greater than 14.0. Thus, the present invention saves a significant amount of energy while obtaining the same result.

The essence of the invention

The present invention provides a heating, ventilation and air conditioning system in which a main closed loop for water is used as a heat transfer reservoir for both heating and cooling. A plurality of cooling micro-heat exchangers are provided, each cooling micro-heat exchanger being connected to a main closed water loop. Each cooling micro-heat exchanger contains its own heat engine. Each micro-cooling coil contains one or more fan control units that provide heat exchange between the micro-cooling coil and the air in the building. In the first mode, a cooling micro-heat exchanger transfers heat from the air in the building to water circulating inside the main closed water loop. In the second mode, a cooling micro-heat exchanger transfers heat from the water circulating in the main closed water loop to the air in the building. A main water loop control system is provided to control the temperature of water circulating in the main water loop.

The overall control system preferably controls all components to operate in an efficient manner. In many working examples, the net effect of the system according to the present invention will be the transfer of heat from one part of the building to another, rather than the use of external energy for heating or cooling.

Brief description of graphic materials

In fig. 1A and 1B are plan views showing a prior art HVAC system in a multi-story building.

In fig. 2A and 2B are schematic views illustrating the use of a cooling heat exchanger and a closed cold water loop in a prior art HVAC system.

In fig. 3 is a schematic view representing the use of hot water installation and

- 3 043362 closed loop hot water circulation in a prior art HVAC system.

In fig. 4 is a schematic view showing an air handling chamber in a prior art HVAC system.

In fig. 5 is a plan view showing areas on one floor of a building.

In fig. 6 is a plan view illustrating the use of multiple air handling chambers and air distribution ducts to cover areas on a single floor of a building.

In fig. 7A is a plan view showing an HVAC system constructed in accordance with the present invention.

In fig. 7B is a plan view showing an HVAC system constructed in accordance with the present invention.

In fig. 8 is a schematic view representing the use of a micro-cooling heat exchanger powering multiple fan control units.

In fig. 9 is a schematic view showing the operation of the apparatus of FIG. 8 with fan control units providing heating.

In fig. 10 is a schematic view showing the operation of the apparatus of FIG. 8 with fan control units providing cooling.

In fig. 11 is a perspective view showing an exemplary physical embodiment of a cooling microheat exchanger according to the present invention.

In fig. 12 is a perspective view showing the embodiment of FIG. 11 from a different vantage point.

In fig. 13 is a perspective view showing the compressor assembly and controller housing for the physical embodiment of FIG. 11 and 12.

In fig. 14 is a schematic view showing the supply of fresh air to fan control units in an embodiment of the present invention.

In fig. 15 is a schematic view showing the use of a heat exchanger between a cooling micro-heat exchanger and a main water loop.

In fig. 16 is a schematic view showing a plurality of cooling micro-heat exchangers connected to a main water loop via an intermediate water loop.

In fig. 17 is a schematic view showing the use of an evaporative condenser and a boiler to control a main closed loop for water.

In fig. 18 is a schematic view showing the use of a heat pump to control a main closed loop for water.

In fig. 19 is a schematic view showing a cooling micro-heat exchanger in which refrigerant circulates in a secondary closed loop to the fan control units.

In fig. 20 is a schematic view showing the embodiment of FIG. 19 with fan control units providing cooling.

In fig. 21 is a schematic view showing the embodiment of FIG. 19 with fan control units providing heating.

In fig. 22 is a schematic view showing a configuration with multiple units in the form of a micro-cooling heat exchanger in which refrigerant circulates in a secondary closed loop to the fan control units.

In fig. Figure 23 shows a graph of the heat transfer coefficient for several HVAC systems operating in cooling mode.

In fig. Figure 24 shows a graph of the heat transfer coefficient for several HVAC systems operating in heating mode.

In fig. 25 shows a graph of pressure drops as a function of percent load for a system according to the invention and for prior art systems.

Reference numbers on graphic materials

- Building;

- floor;

- installation in the form of a cooling heat exchanger;

- installation of hot water;

- air treatment chamber;

- air duct system;

- cooling tower;

- circulation pump;

- circulation pump;

- closed cold water circuit;

- circulation pump;

- cooling tower circuit;

- 4 043362

- power supply;

- gas inlet;

- exhaust chimney;

- closed hot water circuit;

- recirculation fan;

- main fan;

- inlet;

- release;

- air valve;

- air valve;

- air valve;

- control valve;

- control valve;

- central zone;

- eastern zone;

- northern zone;

- western zone;

- southern zone;

- floor;

- feed installation;

- air distribution duct;

- central zone air treatment chamber;

- air treatment chamber for the eastern zone;

- air treatment chamber for the northern zone;

- air treatment chamber for the western zone;

- air treatment chamber for the southern zone;

- main closed circuit for water;

- control system for the main closed loop for water;

- cooling microheat exchanger;

- fan control unit;

- return pipeline;

- supply pipeline;

- valve;

100 - valve;

102 - valve;

104 - valve;

106 - valve;

108 - valve;

110 - valve;

112 - valve;

114 - pump;

116 - pump;

118 - heat exchanger;

120 - heat exchanger;

122 - compressor;

124 - throttle valve;

126 - secondary closed circuit for water;

128 - frame;

130 - reversing valve assembly;

132 - connection point;

134 - controller housing;

136 - air duct for fresh air;

138 - pneumatic distributor;

140 - inlet for recirculation air;

142 - heat exchanger;

144 - intermediate closed circuit for water;

146 - first cooling micro-heat exchanger;

148 - second cooling microheat exchanger;

150 - third cooling microheat exchanger;

152 - first secondary closed circuit for water;

154 - second secondary closed circuit for water;

156 - third secondary closed circuit for water;

- 5 043362

158 - evaporative condenser;

160 - boiler unit;

162 - pump;

168 - heat pump;

170 - reversing valve;

172 - valve;

174 - valve;

176 - valve;

178 - valve;

180 - throttle valve;

182 - check valve;

184 - check valve;

186 - coil;

188 - closed refrigerant circulation circuit;

190 - spare cooling microheat exchanger;

192 - heat exchanger;

194 - heat exchanger;

196 - heat exchanger;

198 - cooling microheat exchanger curve;

200 - magnetic bearing curve;

202 - conventional cooling curve.

Description of Embodiments

Fig. 7A is a simplified diagram showing how an HVAC system according to the present invention can be installed in a multi-story building 10. A Primary water loop (PWL) 86 extends through the entire building. A circulation pump or circulation pumps (not shown) maintain constant circulation through a flow rate that can be varied as required. The PWL control system 88 maintains the temperature of the water within the main closed water loop at a desired point or within a desired range. Prior art HVAC equipment such as a cooling coil and boiler may be used for the PWL control system 88. Some examples are provided sequentially.

The invention uses circulating fluids to transfer heat. The circulating liquid is preferably water, the term water encompassing solutions and mixtures in which anti-corrosion and other additives may also be present. The circulating fluids may be something other than water, and the present invention is not limited to the use of water. For convenience, the term water will be used throughout the description, which term should be understood to cover any suitable circulating fluid.

The water within the main water loop will preferably be maintained at a temperature in the range of 15 to 30°C, more preferably 18 to 26°C, and most preferably 20 to 24°C (68 to 76°F). This is a significant change from prior art HVAC systems where the cold loop water is typically maintained below 7°C (below 45°F) and the hot loop water is typically maintained above 50°C (above 122° F). In the present invention, the water in the PWL is maintained within a range that is substantially the same as the desired temperature inside the building.

One or more cooling microheat exchangers 90 are provided for each floor 12 of the building. Each cooling micro-heat exchanger is configured to exchange heat with water circulating in the PWL 86. Each cooling micro-heat exchanger is also configured to exchange heat with one or more associated fan control units 92 (shown in FIG. 7B). Each fan control unit or units heats or cools the air in the area they cover.

When considering FIG. 7A, those skilled in the art will appreciate that the main water loop 86 extending to a significant height can create significant pressure problems because the pressure near the bottom will be significantly greater than the pressure near the top. In tall buildings it will often be necessary to break the PWL into smaller additional closed loops, with water-to-water heat exchangers connecting the closed loops. Other approaches can be used to maintain water pressure within the desired range. For example, devices that reduce pressure or increase pressure can be placed within a closed loop. The device that increases the pressure is usually only a pump. The pressure reducing device may be an intermediate storage tank on the downstream side of the closed circuit. The intermediate tank receives water from above and reduces the air pressure created in the tank to atmospheric pressure. Other pressure regulating devices are known to one skilled in the art.

- 6 043362 equipment. The term main closed circuit for water should be understood to possibly include these pressure regulating devices.

In fig. 8 shows a schematic view of a single cooling micro-heat exchanger 90 and associated fan control units 92. The cooling micro-heat exchanger 90 is connected to the main closed circuit 86 for water. A valve in the supply line 96 supplies circulating water to the cooling micro-heat exchanger 90, and a valve in the return line 94 returns water from the cooling micro-heat exchanger to the PWL.

The cooling microheat exchanger in this example is based on a non-reversible heat engine. Compressor 122 compresses a suitable refrigerant and transfers it to heat exchanger 120. Heat exchanger 120 acts as a condenser. It cools the circulating refrigerant and transfers it to the butterfly valve 124. The butterfly valve expands the liquid refrigerant and transfers it to the heat exchanger 118, which acts as an evaporator. The evaporator heats the refrigerant gas and transfers it back to the inlet side of the compressor 122.

The heat exchanger 118 is cooled by the circulating refrigerant whenever the compressor 122 is operated. Therefore, when the compressor is operated, the heat exchanger 120 is heated and the heat exchanger 118 is cooled. The circulation pump 114 pumps water through the heat exchanger 118 when it is activated. Likewise, the circulation pump 116 pumps water through the heat exchanger 120 when it is activated. The heat engine in this example is non-reversing, meaning that the flow through the closed circuit for the refrigerant is always in one direction (as opposed to a heat pump, which may have a reversing valve to reverse the flow through the evaporator and condenser).

A secondary water loop 126 circulates water through one or more fan control units 92 . Each fan control unit includes a water coil from a secondary closed water loop and a fan configured to blow air over the coil. If the water circulating through the secondary water loop 126 is hot, then a coil in the fan control unit is used to heat the air drawn through the fan control unit. If the water is cold, the fan in the fan control box is used to cool the air. An air distribution duct or ducts are typically connected to each fan control unit. This is not shown in the view.

The first set of control valves 98, 100, 102, 104 controls the flow of water through the heat exchanger 118 (evaporator). A second set of control valves 106, 108, 110, 112 controls the flow of water through the heat exchanger 120 (condenser). Additional control valves may be provided on different branches of the secondary water loop 126 to control flow for each individual fan control unit 92.

In fig. 9 and 10 show the cooling micro-heat exchanger in its two main operating modes. In fig. 9 shows a cooling micro-heat exchanger 90 operating in a heating mode, in which the fan control units 92 heat the air in their respective zones. Valves 98 and 102 are open. Valves 100 and 104 are closed. Water from the main water loop is supplied from supply line 96 and passes through pump 114. The water then circulates through heat exchanger 118 and exits through valve 102 before entering return line 94. The flow path is shown in bold. The water PWL passing through the heat exchanger 118 is cooled and returned to the PWL. In other words, heat is transferred from the water in the PWL to the cooling micro-heat exchanger.

Valves 108 and 112 are open. Valves 106 and 110 are closed. Pump 116 pumps water from heat exchanger 120 through valve 108 and out into secondary closed water loop 126. Water returned from the fan control units in the secondary water loop flows through valve 112 and into heat exchanger 120. The water passing through heat exchanger 120 is heated (it is worth recalling that the heat exchanger acts as a closed loop condenser for refrigerant), and this heat is transferred to the fan control units. The heated water flowing through the fan control units is used to heat the air. Considering the general operating principle shown in FIG. 9, heat comes from the water circulating in the main closed water loop 86 and is transferred to the air forced through the fan control units 92. This is accomplished by connecting PWL 86 to heat exchanger 118 (evaporator) and secondary water loop 126 to heat exchanger 120 (condenser).

In fig. Figure 10 shows the same arrangement operating in cooling mode. Valves 106 and 110 are open. Valves 108 and 112 are closed. As in the previous example, water from the main closed water loop comes from supply line 96.

However, unlike the previous example, water from the supply line is directed through valve 110 to heat exchanger 120. Pump 116 pumps water through heat exchanger 120 and through valve 106. From valve 106, water flows back to return line 94 (where it reenters the PWL). The flow path is shown with a thick line. The water PWL passing through the heat exchanger 120 is heated and returned to the PWL. In other words, heat is transferred from the cooling micro-heat exchanger to the water in the PWL.

- 7 043362

Valves 98, 100, 102, 104 are installed to circulate water from a secondary closed water loop 126 through a heat exchanger 118 (evaporator). Valves 100 and 104 are open. Valves 98 and 102 are closed. Pump 114 pumps water through heat exchanger 118 (evaporator) and down into secondary closed water loop 126. Water returned from the fan control units in the secondary water loop passes through valve 100 and back to pump 114. The water passing through the secondary water loop is thereby cooled, and the cooled water is used to absorb heat from the building air passing through through fan control units.

Considering the general operating principle shown in FIG. 10, it can be seen that heat comes from the air forced through the fan control units 92 and is transferred to the water circulating in the main closed water loop 86. This is accomplished by connecting PWL 86 to heat exchanger 120 (condenser) and a secondary water loop 126 to heat exchanger 118 (evaporator).

It should be noted that at all times the closed circuit for the refrigerant passing through heat exchanger 118 and heat exchanger 120 always flows in the same direction (pumped by the compressor). Unlike a reversible heat pump, the refrigerant closed loop does not have a reversing valve. Heat exchanger 118 is always an evaporator, and heat exchanger 120 is always a condenser.

In fig. 11-13 show some physical embodiments of a cooling microheat exchanger according to the present invention and its components. The cooling micro-heat exchanger 90 in this example is contained within the frame 128. The heat exchangers 118 and the heat exchanger 120 are mounted near one end of the frame. Circulation pumps 114 and 116 are installed near the opposite end. Compressor 122 is contained within the illustrated housing. Interconnected pipes are provided to create a flow path according to the design of FIG. 8 and 9.

In fig. Figure 12 shows the same cooling micro-heat exchanger from a different vantage point. This view will show the reader how the tubes terminate at four connection points 132. Two of these connection points lead to the primary water loop 86, and two of these connection points lead to the secondary water loop 126. As shown in the schematic view in FIG. 8 and 9, four connection points are sufficient to provide the required flow paths.

Returning to FIG. 11, it may be noted that all of the flow valves for the cooling micro-heat exchanger are provided in this example in a single reversing valve assembly 130. Eight valves may be arranged to alternate with a single movable spool. All valves (valves 98, 100, 102, 104, 106, 108, 100, and 112 in FIGS. 9 and 10) are contained within the reversing valve assembly 130 (to avoid user confusion, it should be noted that the term The reversing valve assembly in this case does not refer to the reversing valve within a closed refrigerant circuit). The reversing valve assembly 130 may be a spool valve, where the passage of the spool through the body operates more than one valve at a time. As is known to those skilled in the art, a single spool passing through a suitable housing can contain all eight valves 98, 100, 102, 104, 106, 108, 110, 112. Thus, a single valve actuator assembly can provide the switching required for operation of the cooling micro-heat exchanger in heating mode or cooling mode. Also, as will be explained, an additional idle mode may be provided.

Continuing to look at FIG. 11, it can be noted that the compressor 122 is quite compact. The compressor is preferably a centrifugal model that operates at high speed. The compressor preferably uses ultra-low friction bearing technology. This bearing technology allows for an oil-free closed circuit for the refrigerant, which greatly improves efficiency. One approach is to use magnetic bearings, which essentially levitate the rotating compressor shaft. These bearings are very effective, but also quite expensive. A cheaper approach is to use foil bearings. Foil bearings have a minimum breakout speed that must be maintained to prevent any physical contact within the bearings. This breakout speed is quite low - typically around 5% of the bearing's rated operating speed. The use of such bearings ensures a very high rotation speed of the rotating compressor shaft. Such bearings also provide virtually unlimited unloading, which means the compressor can operate at speeds much lower than its rated maximum speed without risk of contact in the bearings.

As a result of the combination of these factors, compressor 122 is quite compact and lightweight for its power output. In fig. 13 shows a physical embodiment of compressor 122 with controller housing 134 attached. The controller housing contains electronics adapted to control the operation of the compressor over its entire operating range, as well as the start and stop functions. In preferred embodiments, the compressor will operate continuously. During periods when heating or cooling is not required, the control electronics reduce the rotation speed to a minimum (to approximately 10,000 rpm). The control electronics will also switch the cooling

- 8 043362 micro-heat exchanger between heating and cooling modes so that the water temperature in the secondary closed circuit for water remains close to the air temperature in the space served by the cooling micro-heat exchanger. This idle state actually consumes more energy than simply turning off the compressor. However, by continuously operating the compressor at a speed greater than the foil bearing separation speed, the life of the compressor is extended indefinitely. This operation is called idle mode. The compressor is unloaded - this means that its speed is reduced to a low speed that is high enough to maintain proper bearing function, but at which the refrigerant circulation rate is significantly reduced. In this idle mode, eight valves are periodically switched so that the cooling micro-heat exchanger switches between a heating mode and a cooling mode (for example, once a minute or, for example, once every five minutes). This allows the compressor to continue to operate even when heating or cooling is not required.

Commercial buildings require fresh air supply at certain levels. This is primarily done to minimize the accumulation of carbon dioxide. Some prior art systems monitor carbon dioxide levels and supply fresh air when needed. However, most prior art systems simply pass a fixed volume of fresh air, which is known from experimentation to keep carbon dioxide accumulation at an acceptable level. In fig. 14 depicts an embodiment of the present invention that uses a more complex approach.

Fresh air duct 136 carries compressed fresh air to fan control units 92 . The fresh air supply to each fan control unit is controlled by a pneumatic distributor 138. Recirculation air is supplied to each fan control unit through a recirculation air inlet 140. Fresh air intake often places additional stress on a building's HVAC system. In hot and humid climates, additional energy is required to dehumidify and cool the incoming fresh air. Therefore, it is advisable to let in only the required amount of fresh air.

In the example shown, a carbon dioxide sensor or sensors monitors the level of carbon dioxide in each zone, and the control system uses this information to modulate air distributor 138 so that the required amount of fresh air is introduced, but no more.

In fig. 15-18 show additional exemplary embodiments. In the example of FIG. 15, a main water loop 86 runs vertically through a supply line 96 and a return line 94. A heat exchanger 142 is provided for each floor. Heat exchanger 142 exchanges heat between the main water loop and the intermediate water loop 144. An intermediate closed loop circulates water (maintained between 20 and 24°C) to all cooling micro-heat exchangers 90 on one floor. Each microcooling coil then pumps water through its own secondary water loop 126 to the fan control units associated with the particular microcooling coil.

In fig. Figure 16 shows a diagram for one full floor. In this example, heat exchanger 142 again exchanges heat between the main water loop 86 and the intermediate water loop 144. In this example, all cooling micro-heat exchangers on one floor are connected to an intermediate closed loop 144 for water. Three of these cooling micro-heat exchangers are shown (cooling micro-heat exchangers 146, 148, 150). Also shown are three secondary closed loops 152,154,156 for water - one for each cooling micro-heat exchanger.

All three cooling microheat exchangers 146, 148, 150 operate in the same mode - heating mode. However, this may not always be the case. From time to time, the cooling micro-heat exchangers will operate in different modes. An example is a cool morning with high solar load on the eastern zone of the floor. The cooling micro-heat exchanger operating in the east zone will operate in cooling mode, while the rest of the cooling micro-heat exchangers on the floor will operate in heating mode. Essentially, the east zone cooling micro-heat exchanger will transfer heat from one part of the floor to another, transferring the heat to the intermediate water loop 144, with the heat again being rejected by other cooling micro-heat exchangers on the same floor.

Returning briefly to FIG. 7A, it should be remembered that the temperature of the water circulating in the main closed water loop 86 is maintained by the PWL control system 88. Sometimes this system will add heat to the circulating water and sometimes remove heat from the circulating water. As is known to those skilled in the art, many known devices can be used to control the temperature of water in a main closed water loop.

In fig. 17 shows an embodiment that uses evaporative condenser 158 and boiler 160 to control water temperature. During periods of time when overall cooling is required, the evaporative condenser is turned on to transfer heat to the air surrounding the building. During periods of time when general heating is required, natural gas is burned in boiler 160 to raise the temperature of the water. Pump 162 circulates water in the main closed

- 9 043362 circuit 86 for water. Heat exchanger 142 transfers heat between a main water loop 86 and one intermediate water loop 144. In this example, multiple cooling micro-heat exchangers 90 are connected to the intermediate water loop 144 (only one cooling micro-heat exchanger 90 is shown). Additional intermediate water loops (not shown) are connected to the main water loop 86.

In fig. 18 shows a similar embodiment, in which instead of the evaporative condenser and boiler unit of FIG. 17 used heat pump 168. 17. A heat pump is typically used for smaller commercial buildings, but it is also possible to serve a large commercial building using multiple heat pumps in parallel.

In previous exemplary embodiments, a secondary water loop was used to transfer heat between a particular cooling micro-heat exchanger and its associated fan control units. It is also possible to circulate the cooling agent directly between the cooling micro-heat exchanger and the associated fan control units. In fig. 19-22 show embodiments using this latter approach. In fig. 19 shows the components of the spare cooling micro-heat exchanger 190, while FIG. 20 and 21 show its working states. In fig. 22 shows a system including several cooling micro-heat exchangers.

In the example of FIG. 19, compressor 122 pumps refrigerant to reversing valve 170. The reversing valve directs compressed (and hot) refrigerant gas to either heat exchanger 142 or fan control units 92, depending on the operating mode. Heat exchanger 142 exchanges heat with the main water loop 86 (an intermediate water loop may also be used). As in the previous examples, heat exchanger 142 transfers heat to PWL 86 when the fan controls are in cooling mode and receives heat from the PWL when the fan controls are in heating mode.

Instead of using secondary loop water for the fan control units, the embodiment of FIG. 19 the refrigerant itself is sent to the fan control units through a closed refrigerant circulation loop 188. The refrigerant flow is made reversible by operation of the reversing valve 170, as will be explained below. Valves 172, 174, 176, 178 individually control flow to each fan control unit 92 so that the fan control unit can be turned off when there is no need for heating or cooling in the area it covers. A coil 186 is provided in each fan control unit. This coil acts as either an evaporator or a condenser depending on the operating mode.

A throttle valve 180 is provided for each fan control unit 92. Each butterfly valve 180 includes a conventional bypass with a check valve 184. As will be known to those skilled in the art, check valves 184 allow refrigerant flow to bypass the butterfly valves 180 when the fan controls are operating in heating mode. Throttle valve 124 is provided for operation of fan control units in heating mode. The bypass circuit with check valve 182 allows the throttle valve 124 to be bypassed when the fan controls are operating in cooling mode.

In fig. 20 shows the operation of the spare cooling micro-heat exchanger 190 in cooling mode. The reversing valve 170 is installed in the cooling position. The compressed gas acting as a refrigerant exits the compressor 122 and is directed through the heat exchanger 142. The heat exchanger 142 acts as a condenser for the refrigeration circuit. The cooled and condensed liquid refrigerant exits the heat exchanger 142 and bypasses the butterfly valve 124, passing through the check valve 182. The liquid refrigerant then flows to the butterfly valve 180 in each coil 186, and the expanded gas flows through the coils 186. (It should be noted that that check valve 184 in each of the bypass circuits is closed by flow in that direction). Coils 186 function as evaporator coils in this mode. A fan in each fan control unit blows air over the cold coil 186 and thereby cools the air.

The expanded refrigerant leaving coils 186 is directed back through reversing valve 170 to the suction side of compressor 122. The reader should note that valves 172, 174, 176, 178 allow each fan control unit to be turned off if the area controlled by a particular control unit fan, no cooling required.

In fig. 21 shows the same embodiment operating in heating mode. It should be noted that the reversing valve 170 has been moved to its second position. The hot compressed refrigerant exits the compressor 122 and is directed through valves 172-178 to coils 186 in the fan control units. The coils 86 act as condenser coils in this mode of operation. The fan in each fan control unit forces air over the heated coils and the air is heated. The refrigerant in the coils 186 is cooled and condensed. The cooled and condensed liquid refrigerant flows around the butterfly valves 180 through the check valves 184. It is then expanded by the butterfly valve 124 (it should be noted that the check valve 182 is closed by flow in that direction). The expanded gas then flows into heat exchanger 142. In heating mode, heat exchanger 142 functions as an evaporator coil, absorbing heat from water circulating in the main closed water loop 86. Once the heated refrigerant leaves the heat exchanger 142, it is directed back through the reversing valve 170 to the suction side of the compressor 122.

In fig. 22 shows an extended embodiment of the type shown in FIG. 19-21. In this version, the water temperature in the main closed water loop 86 is controlled by a heat pump 168. Three separate cooling micro-heat exchangers are connected to the PWL 86. The upper cooling micro-heat exchanger exchanges heat through heat exchanger 192. The middle cooling micro-heat exchanger exchanges heat through heat exchanger 194. The lower cooling micro-heat exchanger exchanges heat through heat exchanger 196. It should be noted that the operating mode for each cooling micro-heat exchanger is independent. The upper cooling micro-heat exchanger operates in heating mode. Three associated fan controls are producing heat and one is disabled. The middle cooling micro-heat exchanger also operates in heating mode. Two of its four fan control units are working. The bottom cooling microcoil operates in cooling mode, with three of the four associated fan control units operating and one off.

Fig. 22 serves to illustrate one of the major operational advantages of the present invention. The reader will notice that the upper cooling micro-heat exchanger in this view extracts heat from the water circulating in the main closed water loop 86 and transfers this heat to the air passing through its associated fan control units. The middle micro-cooling coil also extracts heat from the water in the PWL, although at a slower rate since it only operates two of its four fan control units, while the top micro-cooling coil operates three of its four fan control units.

On the other hand, the bottom cooling micro heat exchanger heats the water circulating in the PWL 86. This is true because the bottom cooling micro heat exchanger uses the heat exchanger 196 as a condenser, while at the same time running its refrigeration circuit to provide cooling for its fan control units. It should be recalled that the water in the PWL 86 is constantly circulating. The result of this is that the heat supplied to the PWL through the lower cooling micro-heat exchanger is taken away for use by the upper and middle cooling micro-heat exchangers. Thus, the present invention transfers thermal energy to the outside of the building rather than adding energy from outside. Some cooling micro heat exchangers will add heat to the PWL, while some will remove heat from the PWL. The same may be stated for embodiments including an intermediate water loop between the PWL and one or more cooling micro-heat exchangers. Multiple cooling microheat exchangers connected to a single intermediate loop can transfer thermal energy outside the intermediate loop (eg, transfer heat to an area on the shady side of a floor from an area on the sunny side of the same floor).

Of course, external transmission of PWL or PWL and intermediate water circuits will not be 100% effective. It will also not always be possible to maintain the desired temperature throughout the building without adding some external energy or subtracting some excess energy. However, the approach adopted in accordance with the present invention provides a significant increase in efficiency compared to the prior art. The nature of this increase will be discussed in detail in the Operational Benefits section. However, before moving on to this discussion, some additional details about the components will be provided.

Component Details - Compressor

The compressor used in the present invention preferably has an unlimited unloading capacity. In the HVAC context, the term unloading means that it is operating at less than full capacity. The compressor can change its speed according to the necessary needs of the space it serves. Such a compressor does not have to turn on and off according to the load, but will instead regulate its speed. The lower the load, the lower the speed. As the speed of the drive motor decreases, power consumption decreases according to the cube law.

The compressor is also preferably of an oil-free design. As mentioned earlier, it may use magnetic bearings, foil bearings, air bearings, or some other oil-free technology. Prior art oil-based systems must operate at a high enough load to ensure that oil is circulated in the refrigeration circuit and that it does not collect outside of where it is needed (the compressor). In an oil-free system, the compressor speed can be reduced to 5% of its rated speed. This feature means that the compressor never needs to be turned off completely, but can instead run at low idle speed. Compressor life is significantly increased by using low idle speed instead of completely shutting down.

In some embodiments, the compressor will be integrated into the heat exchangers. This arrangement eliminates external cooling piping, which always poses the risk of leaks.

In preferred embodiments, the centrifugal compressor uses an inverter to vary the speed of the compressor. As with all inverters, some form of line reactor is desirable to improve system harmonics. These reactors are not 100% efficient and therefore they generate heat. In preferred embodiments, the line reactor is integrated into the refrigerant stream such that the heat produced by the line reactor is rejected into the condenser loop. When using such a cooling microheat exchanger in heating mode, the heat generated by the line reactor is supplied to the heating circuit, thereby increasing its efficiency. To further improve efficiency, the reactor can be integrated into an economizer circuit that is installed between the condenser and the evaporator, and one expansion device can be replaced by two expansion devices, so that the economizer operates at a temperature and pressure that is midway between the condensing pressure and the evaporating pressure. and the lost energy and some latent heat in the condenser liquid is evaporated in the economizer and this gas is then fed back to the compressor. In this example, the compressor has a first and second stage impeller, and economizer gas is supplied to the compressor between the two stages.

Component Details - Heat Exchangers and Butterfly Valves

Heat exchangers can vary in style and technology, but preferred embodiments use brazed plate heat exchangers. The condenser and evaporator used in a closed refrigerant loop can preferably be soldered together as a conventional heat exchanger assembly. In some versions, both the compressor and the throttle valve can be integrated into the heat exchanger assembly. Another approach is to have the heat exchangers physically separated and the compressor either installed as a separate unit or integrated into either the evaporator or condenser. Likewise, the expansion device can be installed separately or completely integrated into one or both heat exchangers.

Component Details - Drying

When conditioned air requires dehumidification, the cold surface of the coil in the fan control unit (operating in cooling mode) is used to condense and remove moisture from the air. However, there are times when dehumidification is necessary, but the air must be reheated to maintain a comfortable air temperature. In this case, the fan control unit can be equipped with two coils. The first coil will circulate cold water from the secondary closed water loop. A second auxiliary coil will circulate heated water from the condenser. The cold coil will condense and remove excess moisture, and the warm coil will then reheat the air.

Component Details - Fresh Air Supply

Preferred embodiments use an oil-free air blower to supply compressed fresh air to the fan control units (FCUs) from a central fresh air blower system. Each FCU preferably has its own throttling device to control the level of fresh air demand of each zone at any particular time. Instead of constantly supplying a set amount of fresh air, each FCU will preferably have its own carbon dioxide sensor, and since carbon dioxide levels are monitored, fresh air is only supplied to a specific zone when it is actually needed. Another option is to pre-dry the air in the fresh air supply loop so that the dehumidification load occurs before air is supplied to the building, which means that the FCUs do not need to be very large and the FCUs will be able to handle conditions with warmer cooling water temperatures.

Component Details - System Water Pumps

Each evaporator and condenser is equipped with its own set of chilled water pumps and condenser water pumps, and as an option, each pump is equipped with a variable speed inverter, providing higher energy efficiency in lower load conditions. Each pump is controlled by a cooling micro-heat exchanger system. The water flow is adjusted to maintain the correct temperature throughout the cycle.

Component Details - Fan Control Units

Most commercial air conditioners use either Fan Coil Units/Fan Control Units (FCUs) or Air Handling Units (AHUs) to cool or heat the air. Both of these units basically do the same job, however the FCU typically serves a smaller space while the AHU is typically a duct system and serves a larger space. In this patent, the terms FCU and AHU are essentially used interchangeably and are intended to describe a device that is used to either heat or cool air and control the humidity level in an area. For this reason, the term Fan Control Unit (FCU) is used throughout this detailed description.

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Component Details - Main Closed Loop for Water

As explained earlier, the building's main water loop (PWL) should ideally be maintained at a temperature of 20 to 24°C. Each cooling micro heat exchanger takes heat from the PWL or releases heat to the PWL. The temperature of the water circulating in the PWL can be maintained using various prior art HVAC systems. There are two main approaches. First, the water in the PWL can be supplied through a heat generator (such as a boiler) and then through the evaporative cooler of the cooling tower. Control valves are used to direct water to the heating device or cooling device as needed. On hotter summer days, PWL temperatures above 24°C may be permitted.

The second main approach is to use a heat pump cooling coil to control the PWL temperature. If the water falls outside the 20-24°C range, the heat pump's cooling coil operates to heat or cool the closed loop as needed. During much of the year, PWL simply transfers energy to the outside of the building and no external thermal energy is required. In other cases, a heat pump or other device is used to maintain the proper temperature.

In the case of an existing building, it is possible to use the existing chilled water or heating water circuit as the PWL. For example, an existing water circuit can be converted so that the existing boiler and the existing cooling heat exchanger are connected using pipes in series or parallel. Using the cooling micro-heat exchangers of the present invention, the prior art cooling heat exchanger could be adjusted to supply water at 20°C rather than at 7°C as required in the prior art. Likewise, the boiler outlet temperature can be reduced to 22°C instead of 50°C as in the prior art. This will significantly improve the efficiency of both the boiler and cooling coil, and will also improve the efficiency of the entire system.

Component Description - Micro Cooling Heat Exchanger Hardware Assemblies

A physical embodiment of a cooling microheat exchanger is shown in FIG. 11 and 12. This unit is small enough to fit into the existing equipment space on each floor, and small enough to be transported via elevator. Thus, converting such a unit in an existing building will not be difficult.

Fan control units can be made in various sizes. A small version can replace an air unit in one room. A larger version can cover an entire area with the addition of ductwork. The water circuit feeding the fan control unit does not require large or heavy piping. It can be carried through the suspended ceilings found in most office buildings.

Component Description - Software Based Control Units

Embodiments according to the present invention are preferably controlled by a software-based control system. In preferred embodiments, a Predictive Preemptive Automation Control Algorithm (PPACA) is used as part of the overall control system. PPACA is designed to manage the energy balance within any specific zone, as well as the energy balance within the entire system. This means the PPACA system is able to control temperature, humidity, performance, carbon dioxide levels, fresh air, lighting, security, smoke detection and predict energy costs from a single device. This PPACA is important to the overall performance of the microcooling heat exchanger and adds flexibility in terms of control conditions, efficiency and overall operation.

PPACA is integrated into cooling micro-heat exchanger systems and is used to control micro-cooling heat exchangers as well as zone control. However, in some cases the PPACA will be supplied as a separate control unit, and in other cases it will be integrated into a central control system or into a series of site control systems that control multiple zones. For example, one PPACA can control several zones on a floor, or several floors, or all zones in an entire building.

For ease of installation, the control system can use an established communication protocol such as Bluetooth to communicate between different controlled devices and can be controlled remotely using a mobile phone or tablet. It is also possible to design the control system so that it can be remotely controlled and inspected by a central control center or other parties, such as a service technician, who may be located anywhere, including off-site.

A desirable feature of PPACA is the ability to predict future prices for electricity transactions and the ability to proactively adjust conditions in each space to reduce the need for energy use during periods when energy costs begin to rise sharply. This is done by turning the building into a thermal battery. RRASA every day

- 13 043362 continuously records prices for electricity transactions and weather conditions in the RPACA database. It does this by accessing electricity transaction prices and weather forecasts (preferably using online resources). This allows the system to make its own predictions about load changes in an area, as well as predict when energy costs will increase and decrease. By making this prediction, you can proactively either lower or raise the temperature in each zone when energy costs are lower, and then reduce the load on the system when energy costs rise. During periods of higher energy costs, the load is deliberately reduced and the energy that is stored in the building (cooler air in summer and warmer air in winter) is used to bring the temperature closer to the desired set-point temperature. This uses the energy that is stored in the building, effectively turning the building into a thermal battery.

Operational Benefits

The main advantage of the cooling microheat exchanger approach is its ability to reduce the pressure drop across the refrigeration circuit within the cooling microheat exchanger itself. The refrigeration cycle has a high pressure side and a low pressure side. The high pressure side refers to the relatively high pressure existing from the outlet side of the compressor to the throttle valve. Low pressure side refers to the relatively low pressure existing from the downstream side of the throttle valve to the suction side of the compressor. The term pressure drop refers to the ratio of the high pressure side to the low pressure side.

When the cooling microheat exchanger of the present invention is operated in the cooling mode, the condenser temperature is maintained between 20 and 24°C, and the chilled water circulates in the secondary closed water loop (126 in FIG. 9) from 7 to 24°C. This allows you to vary the pressure drop in the cooling microheat exchanger from 1.05 to 1.4. The pressure drop varies depending on the load.

When the cooling micro-heat exchanger of the present invention is operated in heating mode, the condenser operates at a temperature of 24 to 45°C and the evaporator at a temperature of 15 to 20°C. This allows you to vary the pressure drop in the refrigeration cycle of the cooling microheat exchanger in the range from 1.1 to 2.9. As in cooling mode, the pressure drop depends on the load.

The pressure drop used greatly impacts the overall efficiency of the HVAC system. A conventional prior art refrigeration heat exchanger operates at a pressure drop of 2.2 to 3.8. This higher pressure drop reduces efficiency compared to the present invention.

The efficiency of an HVAC system is largely determined by the difference between the desired air temperature and the temperature of the heat sink source. A large difference requires a highly loaded HVAC system and, as a result, reduced efficiency. A prior art cooling heat exchanger system typically has a large temperature difference and therefore low efficiency.

Many cities around the world have a temperate climate for most of the year. Although there are summer and winter seasons, most of the year experiences moderate weather. With different weather conditions, temperatures vary throughout the day, and in many cases buildings require cooling and heating to operate simultaneously. They may have periods of the day when the sun hits the east side of the building on cool mornings and that side of the building needs to be cooled. However, other parts of the building that are not exposed to the sun may need to be heated. In this case, cooling coils must operate in the same way as hot water boilers, and in these cases the unit often supplies both hot water (40-60°C) and chilled water (7-10°C) to the fan coils at throughout the building. Either a heating or cooling valve is opened on a specific FCU to meet the needs of that specific zone. In each case, both the cooling coil and the boiler operate at part load, but each must operate at its own set temperature. Even if the demand is small, these set temperatures are maintained. In the prior art, two temperature setpoints must be maintained: approximately 7°C and approximately 50°C. The system of the present invention maintains a uniform water temperature of approximately 20°C.

In fig. 23 and 24 compare the heat transformation coefficient of the system according to the present invention and two prior art systems. In fig. Figure 23 shows a comparison for operation in cooling mode. The load range shows operation from 20 to 100% of maximum performance. The vertical line shows the average load with the integrated part load value (IPLV). The upper curve 198 shows the thermal transformation ratio (HCT) at various loads for the cooling microheat exchanger system according to the invention. Middle curve 200 shows the CHP for a refrigeration heat exchanger system that uses a compressor with magnetic bearing technology, such as that sold by Danfoss Turbocor of Tallahassee, Florida. The lower curve 202 shows the CHP for a conventional system

- 14 043362 cooling heat exchanger, which uses an air-cooled cooling heat exchanger. As can be seen, the system according to the present invention has a higher CPT for all load levels, but the efficiency gains become more significant at lower load levels. In fig. Figure 24 shows the same comparison for a combined heating and cooling cycle. Thus, upon reading it will be clear that the present invention offers a significant advantage in efficiency compared to the prior art.

In fig. 25 is a graph of pressure drops for a microcooling microheat exchanger system according to the present invention compared to prior art systems. For a typical load range, the system according to the present invention uses a lower pressure drop and therefore achieves higher efficiency. The graph shown actually has some margin, and the benefit of the system according to the present invention is usually greater than shown.

The present invention encompasses many additional features and embodiments that can be combined in a myriad of ways. Additional exemplary features and embodiments include the following.

1. Water has been described as the preferred circulation medium, but many other substances can be used instead.

2. Embodiments of FIG. 8-10 can be modified so that the refrigerant circulation is reversed, but the water circulation in the secondary closed water loop remains constant. In this embodiment, the role of the two heat exchangers can be reversed by changing the direction of circulation of the refrigerant. A reversing valve (such as shown in Fig. 20) can be used for this purpose.

3. For embodiments that use foil bearings in the compressor, it is desirable to never allow the compressor speed to drop below the foil bearing breakout speed. In these cases, the control system can set the compressor to run slowly, periodically reversing the flow of water through the control valves so that the heating and cooling modes alternate and the air passing through the fan control units is not generally heated or cooled.

4. The insulation requirements for a PWL will be much less than prior art closed hot and cold water loops because the water temperature in the PWL will be close to the air temperature inside the building.

5. The Predictive Anticipatory Automatic Control (PACA) algorithm of the present invention predicts future HVAC loads (for the near term) and predicts energy prices. In order to reduce the cost of operation, RRASA has the ability to use the building as a thermal battery. For example, PPACA can reduce a building's temperature below optimal during periods when energy is cheap so that this stored cooling can be restored by operating at less power during periods when energy is expensive.

6. PPACA can be configured so that different HVAC zones in a building have different priorities. Some zones may be set to maintain the desired temperature regardless of energy cost, while others may be able to vary more widely to save money. For example, hospital surgical rooms can be considered critical, so that the set temperature is maintained under all circumstances. Administrative offices in the same hospital building may become heated during high-cost periods.

7. In a conventional prior art system, hot and cold water are maintained at a constant temperature, and water bypass valves are used to adjust the flow of water through the various air handling chambers. The amount of water flowing through a particular air handler is determined by the flow through a diverter or three-way valve. These valves allow only the amount of water that passes through the coil in a particular air handling chamber to provide the required amount for cooling or heating. The remaining water bypasses the coil and connects back into the return line on the other side of the coil. This leads to wasteful recycling. In the present invention, the flow through the coil is fairly constant, and the performance is controlled by changes in water temperature (not water flow). This fact allows the present invention to operate with much higher efficiency than the traditional method. This fact also allows the use of a lower pressure drop in the refrigeration circuit of the microcooling heat exchanger, which reduces the required compressor speed. Electricity consumption decreases according to the cube law if the compressor speed is halved. The loading and unloading of the prior art cooling heat exchanger is controlled by maintaining a constant supply or return water temperature. Because the prior art system must be able to cope with the unpredictable full load conditions of any air handler, most machines use the supply water temperature as a control point. In the present invention, loading and unloading is controlled from zone to zone. The performance of each cooling micro-heat exchanger is controlled by the actual temperature

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Claims (15)

environmental conditions in the area under his control. The closer the temperature in the space is to the set point, the slower the compressor operates and the more efficient it becomes. Although the previous description contains important details, it should not be construed as limiting the scope of the present invention, but rather as illustrating preferred embodiments of the present invention. Therefore, the scope of the present invention should be established by the claims and not by the examples given. CLAIM 1. A method of controlling the temperature of a space within a building, wherein (a) a fan control unit is used having a fluid coil and a fan, wherein said fan is configured to blow air over said fluid coil and into said space; (b) a refrigeration micro-heat exchanger is used, comprising (i) a compressor, (ii) a condenser, (iii) a butterfly valve, (iv) an evaporator, and (v) a closed refrigerant circuit configured to circulate said refrigerant from said compressor to said condenser, to said throttle valve, to said evaporator and back to said compressor; (c) a main closed fluid circuit through the specified building is used; (d) using a secondary closed loop for fluid passing through said cooling micro-heat exchanger and said fan control unit; (e) a first set of valves is used to control the flow through said evaporator of said micro-cooling heat exchanger; (f) a second set of valves is used to control the flow through said condenser of said cooling micro-heat exchanger; (g) maintaining the temperature of said main liquid loop in the range of 18 to 26°C; (h) when heating is required in said space, setting said first set of valves to circulate liquid from said primary liquid loop through said evaporator and setting said second set of valves to circulate liquid from said secondary liquid loop through said condenser; and (i) when heating is required in said space, setting said first set of valves to circulate liquid from said secondary liquid loop through said evaporator and setting said second set of valves to circulate liquid from said primary liquid loop through said condenser. 2. The method of controlling the temperature in a space inside a building according to claim 1, characterized in that it includes maintaining the temperature of said main closed loop for liquid in the range of 20 to 24°C. 3. The method for controlling the temperature in a space inside a building according to claim 1, wherein said primary liquid loop and said secondary liquid loop contain water. 4. The method for controlling the temperature in a space inside a building according to claim 1, characterized in that said first set of valves comprises a spool valve. 5. The method for controlling the temperature in a space inside a building according to claim 4, wherein said second set of valves is contained within said spool valve. 6. The method of controlling the temperature of a space within a building according to claim 1, further comprising providing a second fan control unit attached to said secondary closed fluid loop. 7. The method of controlling the temperature in a space inside a building according to claim 1, further comprising unloading said compressor and periodically alternating cycles of said first set of valves and said second set of valves between a heating mode and a cooling mode. 8. A method of controlling the temperature of a space within a building, wherein (a) a fan control unit is used having a fluid coil and a fan, wherein said fan is configured to blow air over said fluid coil and into said space; (b) a cooling micro-heat exchanger is used, comprising (i) a compressor, (ii) a condenser, - 16 043362 (iii) a throttle valve, (iv) an evaporator, and (v) a closed refrigerant circuit configured to circulate said refrigerant from said compressor to said condenser, to said throttle valve, to said evaporator and back to the specified compressor; (c) a main closed fluid circuit through the specified building is used; (d) using a secondary closed loop for fluid passing through said cooling micro-heat exchanger and said fan control unit; (e) the temperature of said main closed fluid loop is maintained in the range of 18 to 26°C; (f) when heating is required in said space, fluid is circulated from said primary liquid loop through said evaporator and liquid is circulated from said secondary liquid loop through said condenser; and (g) when heating is required in said space, circulating liquid from said secondary liquid loop through said evaporator and circulating liquid from said primary liquid loop through said condenser. 9. The method of controlling the temperature in a space inside a building according to claim 8, characterized in that it includes maintaining the temperature of said main closed loop for liquid in the range of 20 to 24°C. 10. The method for controlling the temperature in a space inside a building according to claim 8, wherein said primary liquid loop and said secondary liquid loop contain water. 11. The method for controlling the temperature in a space inside a building according to claim 8, characterized in that said flow through said evaporator is controlled by a slide valve. 12. The method for controlling the temperature in a space inside a building according to claim 11, characterized in that said flow through said condenser is controlled by said spool valve. 13. The method for controlling the temperature of a space within a building according to claim 8, further comprising providing a second fan control unit attached to said secondary closed fluid loop. 14. A method for controlling the temperature in a space inside a building according to claim 8, characterized in that it further includes unloading said compressor and periodically alternating cycles of said cooling micro-heat exchanger between a heating mode and a cooling mode. 15. A method of independently controlling the temperature inside a first space in a building and a second space in said building, wherein (a) a first fan control unit is used having a first fluid coil and a first fan, wherein said first fan is configured to blow air over said a first liquid coil and into said first space; (b) a first cooling micro-heat exchanger is used, comprising (i) a first compressor, (ii) a first condenser, (iii) a first butterfly valve, (iv) a first evaporator, and (v) a first closed refrigerant circuit configured to circulate said refrigerant from said first compressor to said first condenser, to said first throttle valve, to said first evaporator and back to said first compressor; (c) a main closed fluid circuit through the specified building is used; (d) using a first secondary closed loop for fluid passing through said first micro-cooling heat exchanger and said first fan control unit; (e) a second fan control unit is provided having a second fluid coil and a second fan, wherein said second fan is configured to force air over said second fluid coil and into said second space; (f) a second cooling micro-heat exchanger comprising (i) a second compressor, (ii) a second condenser, (iii) a second butterfly valve, (iv) a second evaporator, and (v) a second closed refrigerant circuit configured to circulate said refrigerant from said second compressor to said second condenser, to said second throttle valve, to said second evaporator -