GB2125535A - Ventilating apparatus - Google Patents

Abstract

Ventilating apparatus comprises a cabinet (1) for mounting on and in the outside wall of an enclosure. The cabinet includes a supply fan (2) for flowing air into the enclosure and an exhaust fan (3) for flowing air out of the enclosure, and automatic dampers (6, 7) to selectively communicate the supply and exhaust fans with the outside of the enclosure and automatic damper (8) to selectively communicate the supply and exhaust fans with each other to automatically control the temperature of air flowing into the enclosure as conditions inside and outside the enclosure change. <IMAGE>

Description

SPECIFICATION Heating, cooling and ventilating apparatus This invention relates generally to a cooling, heating and ventilating apparatus and more particularly to a human comfort cooling, heating and ventilating apparatus for use serving an enclosure or room which uses outside air to reduce room cooling, heating and ventilating costs.

The use of heating and cooling means as well as ventilating means to maintain desired environmental conditions within an enclosure is well known in the art. Examples of known U.S. patents relating to such apparatus are as follows: 3,305,001; 3,307,469; 3,331,304; 3,367,258; 3,404,728; 3,407,620; 3,627,030; 3,637,031; 3,774,674; 3,842,901; 3,853,172; 3,882,928; 3,891,027; 3,901,310; 3,927,713; 3,977,466; 4,079,665; and 4,244,193. The apparatus disclosed in the above identified patents suffer from deficiencies. Some of the devices do not adequately recirculate air because of their structure including the location of blowers. Some of the devices do not adequately exclude outside light, rain or even air.

Additionally some of the devices may require unnecessarily high energy input.

in some occupied building spaces, natural cross ventilation is undesirable because of the requirement for privacy, fire codes and the necessity of excluding outside noise, daylight, rain and dust. Examples of such spaces include hotel guest rooms, hospital patient rooms, and nursing home patient rooms, private offices, doctor's examining rooms and residential bedrooms. Conditions may require comfort cooling in such spaces because of solar, occupant, lighting and appliance heating, even though outside air temperatures may be 70"F or less. Even in warmer climates the conditions of need for cooling, even though outside air temperatures may be 70"F or less exists many hours per year.In many populate areas of the world, because of latitude, altitude or ocean currents the outside temperature of 70"F or less is seldom or never exceeded.

An apparatus which utilizes outside air for individual room cooling can be operated at much less energy consumption than a unit or system cooling the same space by conventional refrigeration or air conditioning. Although increases in efficiency have been achieved in typical cooling or air conditioning apparatus they still require substantial energy for operation.

It is fundamental that no more air can be introduced into a typical building or enclosure from the outside than can be permitted to escape again, regardless of by what route, to the outside. Similarly, no more air can be exhausted from the typical building or enclosure than is somehow admitted from the outside into it. It is because of this principal that an open window in an otherwise closed room admits very little air even with brisk winds outside. If the air pressure within a space is to be maintained equal to that outside, substantially equal amounts of air must be positively supplied and positively exhausted from the space. Substantially equal inside and outside air pressures are desirable for easy opening and closing of doors and in the case of fire to prevent drafts.Generally an apparatus which provides outside air to a room should include both a supply and an exhaust blower or fan to circulate the air. In the case of central units, it is necessary to use air ducts which increase operating costs because of resistance of air flow through the ducts, and common air supply and exhaust to multiples of single occupancy rooms is hazardous from the standpoints of spread of fire, smoke or contigious health infections.

The more outside air supplied to a space, the closer the resulting space temperature to outside air temperature. However, increasing the air supply also increases the energy consumed for any given fan or blower size and provides higher operating noise level.

A typical room or space of the types mentioned above can be expected to have a maximum cooling load of approximately 1/2 ton, and a typical 1/2 ton refrigerated air conditioning unit would recirculate approximately two hundred cubic feet per minute in the room.

It is the object of the subject invention to overcome deficiencies and limitations in a prior art and to provide an improved and more efficient heating, cooling and ventilating apparatus. The improved and new apparatus of the invention increases efficiency and reduces energy consumption at the same time it maintains or increases the comfort level of the environment of a space which is being heated, cooled or ventilated. Other objects of the invention will be apparent from the following detailed disclosure.

The invention comprises a human comfort cooling, heating and ventilating apparatus enclosure within a cabinet for mounting in an outside wall of a private occupancy space.

The apparatus includes separate supply and exhaust fans for supplying air to a space and exhausting air from the space. A plurality of automatically controlled dampers provide for intake of outside air, exhaust or inside air and recirculation of inside air. The apparatus is acoustically insulated to attenuate outdoor noise and prevent admittance of light. Louvers and filters prevent entry of rain, snow and dust into the space, whose environment is being maintained at a predetermined level.

Additional heating and cooling means can be provided for use when inside and outside conditions are such as to require additional heating or cooling.

Figure 1 is a perspective view of the apparatus of the invention as it would appear when installed in and on an outside wall of a building or enclosure.

Figure 2 is a broken plan view showing some of the components of the apparatus.

Figure 3 is a broken elevation view showing some of the components of the apparatus.

Figure 4 is an exploded view showing some of the components of the apparatus.

Figure 5 is a partial view of the damper motor and drive.

Figure 6 is a flow chart of the control means.

Referring to Fig. 1, there is shown a finished room side cabinet 1 which is internally lined and baffled to attenuate outside sound and light. The cabinet 1 includes two separate portions which contain a supply air fan 2 as shown in Fig. 2 in the first separate portion and an exhaust air fan 3 in the second separate portion. The fans 2 and 3 may be of centrifugal, tangential or axial design. A directional room air supply grille 4 supplies air to the space or room which forms an enclosure.

A return or exhaust air grille or opening 5 is provided to remove air from the room or space. A system of interconnected air dampers 6, 7 and 8 control supply air intake, exhaust air discharge and recirculated room air bypass, respectively. The cabinet also includes an outside air filter 9 to trap dust and particulate matter in the outside air which is being drawn into the space or room.

A conventional wall sleeve would be generally provided which would extend through and be permanently mounted in the outside wall and receive the portion 1A of the cabinet which extends into the wall. The cabinet 1 is installed in the sleeve so it can be easily removed for maintenance and the like. The wall sleeve might also have in its base a trapped rain water catch pan ported to drain to the outside.

A storm proof divided louv 11 attaches from inside to the outer edge F of a wall sleeve. The louv 11 inhibits entry of rain and light through the air intake and exhaust dampers 6 and 7, respectively. A system of controls 1 2 including a return air sensing thermostat is provided to control the apparatus.

The thermostat in the control device 1 2 activates an actuator such as electric motor means 13, operatively interconnecting dampers 6, 7 and 8 through a reduction gear G or the like with an end cut off switch to deenergize exhaust fan 3 and reduce the speed of supply fan 2.

The motor means 1 3 is a stall motor which runs in both directions for opening and closing the dampers. A modulating electric motor or a pneumatic opener and closer could also be used. The gear reduction for the motor 1 3 provides a slow opening and closing of the dampers. This provides for the predetermined period of operation once the apparatus is actuated by the thermostat control. The predetermined period avoids rapid changes in the modes of operation. A coil spring 1 8 connects the motor output shaft to the gear G to provide a lost motion connection. This allows the motor output shaft to continue turning a predetermined amount after the dampers are fully opened or closed.Switch means may be positioned to be engaged after the closing of the dampers 6 and 7 to operate heating coil means or refrigerated coil means.

The fan 2 is of a centrifugal design and includes a short duct system 2A connected with the grille 4. This duct system attenuates noise from the fan 2. The fan 3 is of an axial design. The fans 2 and 3 are of conventional construction and include conventional drive components.

The dampers 6, 7 and 8 include a plurality of vertical damper blades 1 4 which are rotatably mounted about their central axes for rota tin to open and close into contacting, sealing arrangement. The upper axes of the blades are connected by timing belts 1 5 so that blades are positively interconnected and operate in predetermined sequence. Suitable direct gearing or linkage means could also be provided to control the blades 14 and synchronize their simultaneous opening and closing.

The dampers 6 and 7 close as the damper 8 is opened and dampers 6 and 7 open as damper 8 is closed.

A heating coil 1 6 may be provided between the air supply fan 2 and exhaust fan 3. A suitable filter means 1 6 could also be provided to remove dust and particulate matter, preventing fouling of the coil. Filter 1 6 can be located ahead or behind, with respect to air flow of an electric strip or stream of hot water type coil.

Referring to Fig. 5 of the drawing there is shown the damper motor means 1 3. The damper motor means 1 3 consists of a reversible stall motor 30 which is operatively connected to a gear drive mechanism 32. The gear drive mechanism is mounted upon a mounting plate 33 which is secured to another mounting bracket 34. The output shaft 35 of the gear is connected to a worm gear 36 which operatively engages gear 37 connected to output shaft 38 through spring 40. The gear 37 is connected to a first shaft (not shown) which is connected to a flange 39. The flange 39 is connected to coil spring 40 through screw 41. The upper end of the coil spring 40 is connected to flange 42 through screw 43. Shaft 38 is connected to the flange 42 so that the gear 37 drives the shaft 38 through the coil spring 40 which acts as a lost motion connector. Gear pulley 44 drives the dampers. As will be apparent, the drive arrangement provides for a greatly reduced rotation rate for the gear 44 through the gearing arrangement.

Rotatably mounted with the shaft (not shown) connected with gear 37 is a switch engaging lever 45. The lever 45 rotates between a first position near the surface 46 to a second position at which bypass damper 8 is closed and switch 23 is engaged which controls the supply and exhaust fans. Further rotation of lever 45 against tension of coil spring 40 engages switch 24 which controls auxiliary heating means.

During operation the stall motor 30 rotates in opposite directions in response to signals from the thermostat 22. When the lever 47 nears the surface 46 and the bypass damper fully closes, the motor stalls and remains in this position until the direction of rotation of the motor is switched through the thermostat 22. Upon switching of the direction of the motor, the lever 47 slowly travels until it engages the switch 24 and again stalls. Prior to engagement of the switch 24, the lever 47 engages the switch 23 which deenergizes the exhaust fan and shifts the supply fan to a lower speed. This would occur when the outside dampers 6 and 7 are fully closed and the bypass damper 8 is fully opened.

In the flow diagram of Fig. 6 a line voltage switch 20 energizes all circuits of the unit. It is understood that the motors 2, 3 and 1 3 would be supplied with electrical power. A transformer 21 reduces voltage to the control and damper motor circuit which consists of a single pole, double throw thermostat 22, which causes damper motor 1 3 to rotate either clockwise or counter clockwise depending upon the position of thermostat 22. When damper motor 1 3 has reached such point of travel as to result in suppply damper 6 and exhaust damper 7 to be in fully open position and bypass damper 8 to be in fully closed position, single pole double throw switch 23 causes exhaust fan 3 to stop and supply fan 2 to reduce to low speed.Further travel of damper motor closes switch 24 causing coil valve 25 to open or in the case of electric heat, a contactor to close. So far all this deals with cooling by means of outside air only.

In cases where cooling must also be provided by means of refrigeration a thermostat 26, in the case of chilled water cooling, senses the presence of chilled water and actuates relay 27. In the case of direct expansion and refrigerant compressor cooling, thermostat 26 senses outside air instead. When double pole, double throw relay 27 is activated by thermostat 26 it reverses the rotation of damper motor 1 3 upon call from thermostat 22, so that when dampers 6 and 7 are fully closed and damper motor 3 will result in opening of valve 25 in the case of cooling by chilled water coil.In the case of cooling by a direct expansion refrigerant coil and remote condensing unit, the further travel of damper motor 1 3 will result in engaging the compressor motor starter or contractor, and thermostat 26 will also, through a relay, (not shown) prevent energizing of the heating means.

The operation of the device of the invention is as follows. Assume the thermostat in the control means 1 2 called for full cooling. The supply intake damper 6 and the exhaust discharge damper 7 would move to their fully open position. Room recirculation damper 8 would be moved to its fully closed position.

100% outside air is being supplied to and exhausted from the room.

After the thermostat in the control 1 2 is partially satisfied, the outside dampers 6 and 7 begin closing while the bypass damper 8 partially opens. The room is supplied with a portion of positively supplied and exhausted outside air which is diluted with air recirculated only within the room or space by bypassing between the fans 2 and 3.

After the thermostat in the control 1 2 is fully satisfied and reaches its set point, the outside dampers 6 and 7 are fully closed and the bypass damper 8 is fully open. An endswitch is engaged by a lever on the damper motor output shaft which deenergizes the exhaust fan 3 and only supply fan 2 continues recirculating a reduced amount of air within the room or space. The supply fan 2 is a two speed fan and deenergizing the exhaust fan 3 shifts the fan 2 to its lower speed.

When the temperature in the room or space increases and the thermostat is activated.it begins calling for cooling and the first step calling for cooling is started. The dampers 6 and 7 begin opening as damper 8 begins closing. The room air is partially recirculated until the damper 8 is fully closed.

A heating coil may be utilized after the outside dampers 6 and 7 are fully closed and the bypass damper 8 is fully opened as in the step above when the thermostat is fully satisfied and the thermostat senses over cooling (e.g. its calls for heat). To utilize a heating coil the drive shaft of the damper motor continues to turn against the spring tension of coil spring 1 8 beyond the fully closed position of outside dampers 6 and 7 and the fully opened position of bypass damper 8. A switch is engaged by a lever on the shaft when the shaft has rotated a predetermined amount to activate the heating coil and exhaust fan 3 remains inoperative. The activation of the electric heating coil may be by engagement of a relay or contractor.The activation of steam or hot water heating coil is by energizing electrically or by a pneumatic powered valve on the steam or water inlet or outlet. When the thermostat becomes satisfied of heating, again the sequence reverses.

A combination chilled water cooling and hot water heating coil with condensate drain pan having a drain connection to the sewer or the like can replace a hot water heating coil as described above. The control would be as above when in heating mode. A thermostat on or in the chilled water supply pipe would sense that the central chilling plant is in operation and through a relay reverse the operation of return air control 1 2 so that a call for cooling rather than heating would cause outside air dampers 6 and 7 to fully close and bypass damper 8 to fully open. The end switch on damper 8 would deenergize exhaust fan 3 and reduce speed of supply fan 2. The damper drive run-out speed would then operate an electric or pneumatic valve on the coil inlet or outlet.The central chilled water system would be operated when outside air is too warm or too humid for room cooling use.

A direct expansion refrigerant cooling coil with condensate drain pan served by a remote condensing unit can be furnished in addition to or instead of any of the above heating coils. Cooling mode control would be as for a chilled water coil described above. An exception would be that the refrigerated cooling mode would be established by a thermostat sensing temperature of outside air rather than that of the water pipe and the run-out switch would operate the compressor of the remote condensing unit.

If the direct expansion refigerant cooling coil and remote condensing unit have a reverse cycle (heat pump) capability, the coil supplemented by above electric step coil if necessary could supply the heating needs of the room. Heating mode control would be as for the electric heating coil above except that two sequential run out switches would be provided. The first after full opening of bypass damper 8 will, through a relay, activate the refrigerant coil and condensing unit in heating mode. The second, upon further over run of the damper motor, would operate the electric heating coil contactor.

A typical room of the types mentioned can be expected to have a maximum cooling load of approximately 1/2 ton and a typical 1/2 ton refrigerated air conditioning unit would circulate approximately two hundred cubic feet per minute in the room. When cooling with outside air, circulation of considerably more air is desirable for the following reasons.

The economy of outside air can be realized at higher outside temperature. Greater room air motion will result in a satisfactory human comfort at higher relative humidities. A tendency to odour build up and mildew formation, associated with higher relative humidities would be reduced by higher room air exchange rate in the true sense of ventilation.

For an individual room outside air cooling unit, an air flow rate of approximately eight hundred cubic feet per minute has been determined optimal for the following reasons. In connection with cooling, given a sensible cooling load of 1/2 ton, room temperature can be maintained 7"F above outside temperature at an outside air flow rate at 800 cfm. In connection with ventilation in a typical room of 2,000 cubic feet volume, air will be changed at a rate twenty-five times per hour. In the case of fire, such a rate of air change would provide adequate fresh air to any occupants in a room and also purge smoke which might enter the room around doors and other smoke entry means. The power consumption will be approximately 40% that of a 1/2 ton refrigerated air conditioning unit.For a room cabinet size to accommodate components required to move up to 800 cubic feet per minute at low operating noise level, the room cabinet dimensions will remain acceptably small.

The heating may be incorporated into such a unit in the form of the electric strip heating coil, steam heating or hot water heating coil and preferably the latter considering present energy costs. The unit as conceived has a provision for a generously sized heating coil.

In the case of hot water heating this permits in most climates operation of the boiler and piping system at no more than 140"F with considerable reduction is system heat losses when compared to typical radiator or convection systems. Also, solar heating can be utilized under proper climatic conditions. Forced circulation of heating air in the room generally eliminates stratification losses associated with radiator or convection systems, resulting in a significant heating energy saving.

Two weather seal panels of rigid insulated board can also be used for insertion in place of the outside air filter 9 and in corresponding slots between the exhaust fan 3 and exhaust damper 7 to reduce room heat loss in extreme winter weather. The panel slots between the exhaust fan 3 and exhaust damper 7 can be provided with a control circuit switch to prevent outside air dampers 6 and 7 from opening, to prevent bypass damper 8 from closing and to prevent exhaust fan 3 from operating as long as the weather seal panel is in place.

Although the invention has been described in conjunction with the foregoing specific embodiment, many alternatives, variations and modifications are intended to fall within the spirit and scope of the appended claims.

Claims (10)

1. An environmental control apparatus comprising: a cabinet means for mounting on and in the outside wall of an enclosure; said cabinet means including a supply fan for flowing air into the enclosure and an exhaust fan for flowing air out of the enclosure; and automatic damper means to selectively communicate the supply and exhaust fans with the outside of an enclosure and automatic damper means to selectively communicate the supply and exhaust fans with each other to automatically control the temperature of air flowing into the enclosure as conditions inside and outside the enclosure change.

2. The apparatus as set forth in claim 1 wherein the damper means includes a motor for automatically opening and closing the damper means to effect desired air flow.

3. The apparatus as set forth in claim 1 wherein: the cabinet means includes two separate compartments which contain the supply fan respectively with the third damper means connecting the compartments for selectively communicating the comparements with each other.

4. The apparatus as set forth in claim 1 wherein the damper means include separate exhaust and supply dampers communicating with the outside of an enclosure, and a recirculating bypass damper communicating the supply and exhaust fans, said damper means being interconnected and selectively openable and closable to admit and exhaust air or to recirculate air within the enclosure in response to changes in the temperature in the enclosure.

5. The apparatus as set forth in claim 3 wherein: refrigerated coil means is positioned between the portions for providing cooling and dehumidification.

6. The apparatus as set forth in claim 3 wherein: heating means is positioned between the portions for providing heating.

7. The apparatus as set forth in claim 1 wherein: the exhaust fan is deenergized upon full opening of the damper means communicating the supply and exhaust fan.

8. The apparatus as set forth in claim 1 wherein: the speed of the supply fan is reduced upon deenergizing the exhaust fan.

9. A method for ventilating an enclosure, comprising the steps of: flowing a quantity of air through a first closable damper out of the enclosure with an exhaust fan; flowing substantially the same quantity of air from the outside through a second closable damper into the enclosure with a supply fan: closing the first and second closable damper means when the inside air temperatures reaches a predetermined level at or above the outside air temperature: opening a third closable damper at the same time the first and second closable dampers are closed to bypass air from the exhaust fan to the supply fan to maintain air circulation in the enclosure.

10. The method as set forth in claim 9 including: flowing air through the supply fan at a reduced rate and shutting off the exhaust fan when the third closable damper is fully open.