GB2052808A - Method and apparatus for regulating an air ventilation or air conditioning apparatus - Google Patents

Abstract

The error signal of a primary regulation circuit 10, 18, 20, 22, 24, 30, 32, 42, 44, 46, 50, 28, 52, 16 and 14 is infed as a control signal or magnitude to an air quantity auxiliary regulation circuit 24, 30, 32, 42, 44, 46, 50, 28 and 26. The quantity of supply air which is infed to the room or area which is to be ventilated or climatized, is proportionally influenced as a function of the regulation magnitude of the primary regulation circuit. A lower threshold and an upper threshold are adjusted for the infed quantity of air. In order that the proportional band, related to the room temperature, shall remain independent of at least the adjustment of the upper selected threshold or threshold value, the slope of the regulation characteristic of the proportional band is altered at least during adjustment of the upper threshold. By virtue of such arrangement, computation and post- setting of the proportional band is not altered at least during adjustment of the upper threshold. The primary circuit compares at 10 the actual room temperature, measured at 16, with a desired value set at 11. The auxiliary circuit compares at 24 the actual air flow or velocity, measured at 28, with the temperature error. The only corrector is a flap or valve 48. <IMAGE>

Description

SPECIFICATION Method and apparatus for regulating an air ventilation or air conditioning apparatus The present invention relates to a new and improved method of, and apparatus for, regulating an air ventilation or air conditioning apparatus.

Generally speaking, the invention concerns a method and apparatus for regulating an air ventilation or air conditioning installation, wherein there is infed to a primary regulation circuit a signal serving as a control or reference input for an air quantity-auxiliary regulation circuit, in order to proportionally influence, as a function of the regulation magnitude of the primary regulation circuit, the quantity of supply air which is infed to the room or area which is to be ventilated or climatized. As to the infed quantity of air there is selected a lower threshold and an upper threshold.

Such regulation technique especially serves for the regulation of the room temperature as a regulation magnitude, by altering the quantity of supply air which is infed to the room or the like. For instance, the supply air has a constant temperature which is suitable for cooling the room, whereas for heating the room there is possibly provided a base load heater in the form of a radiator heater.

If the room temperature increases, for instance due to external or foreign thermal energy which can be caused by the release of body heat from a larger assembly or group of persons, then the quantity of the supply air is increased as a function of the room temperature. This type of regulation is suitable, for instance, for auditoriums, conference halls and department stores, since there is associated with the increased cooling output also a more intensified ventilation. On the other hand, with low or modest cooling requirements the air quantity is throttled, and thus, there is beneficially provided an additional saving in energy.

The designer of air ventilation and climatizing equipment determines, during the design of the air ventilation or conditioning installation, on the one hand, the minimum quantity of air which should be maintained for hygenic reasons, and, on the other hand, the maximum quantity of air which should not be exceeded for reasons of comfort, since if there prevails too large a quantity of air, owing to higher air inlet velocities, there would arise in the room or area being ventilated or climatized draft phenomena. The momentary required air quantity between these two threshold values or thresholds is determined by a temperature regulator, the output signal of which is infed as a control input or magnitude to an air quantity regulator which alters the quantity of air as a function of the measured room temperature.

A known air quantity or volume regulator of this type possesses a respective adjustment or setting element for limiting the minimum air quantity and the maximum air quantity. Since the range of the air quantity, which can be detected by the air quantity or volume regulator, and which is measured by an appropriate feeler or sensor, generally is greater than the momentarily required maximum threshold value or threshold, only part of this range or region is needed for regulation purposes.

What is disadvantageous with such regulator is that, depending upon the setting of both threshold values, there results a different size proportional band. If the proportional band is greater than required, then depending upon the load state of the installation there results an unnecessarily large regulation deviation from the set reference value, and thus, an impairment in comfort. On the other hand, if the proportional band is too small, then there is no longer ensured for the requisite regulation stability, with the result that the regulation tends to oscillate or hunt. While it is possible to accommodate the proportional band to the set threshold values, nonetheless such is only attainable by carrying out appropriate computations by the person skilled in the art or by empirical determinations. Thus, such type equipment cannot be termed as customer favorable.

It is a primary object of the present invention to provide a new and improved method of, and apparatus for, providing an optimum and stable regulation of an air ventilation or air conditioning apparatus without the need for any complicated adjustments.

A further significant object of the present invention aims at providing a new and improved construction of apparatus for regulating an air ventillation or air conditioning apparatus in an extremely simple, reliable, stable and optimum manner, without the need for carrying out complicated settings or adjustments, and which apparatus is relatively simple in construction, economical to manufacture, extremely reliable in operation, not readily subject to breakdown or malfunction, and requires a minimum of maintenance and servicing.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the method aspects of the present development are manifested by the features that the position of at least the side or end of the proportional band associated with the upper, preselected threshold value is maintained independent of the upper preselected threshold value.

As alluded to above, the invention is not only concerned with the aforementioned method aspects, but further pertains to an apparatus for the performance thereof. The regulation apparatus of the present development contemplates that the primary regulation circuit contains a first comparator, to which there is infed the signal of the preselected temperature reference value and the signal of the actual value of the room temperature which is to be regulated and which actual value signal is measured by a temperature feeler or sensor. The output of the first comparator is connected with the first input of a second comparator of an air quantity-auxiliary regulation circuit, to which there is delivered, by means of its second input, the signal of the actual value of the air quantity measured by an air quantity or air velocity feeler.The output of the second comparator is connected, by means of a limiter or limiting device, with an adjustment or setting element serving to adjust the air volume or quantity which is infed to the room. The limiter is provided with setting or adjustment elements for the lower threshold and the upper threshold, wherein at least the setting element for the upper threshold, is connected with circuit elements for determining the proportional band, so that upon setting such threshold there can be maintained the position of the side of the proportional band, correlated to the upper threshold, independent of the upper preselected threshold.

With the proposal contemplated by the invention, the usually required proportional band already can be set at the site of the factory, so that setting at the installation no longer is necessary, even if the threshold values are subsequently readjusted.

The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof.

Such description makes reference to the annexed drawings wherein: Figure 1 is a block diagram of a regulation circuit according to the invention; Figure 2 is a graph showing a proportional band; and Figure 3 is a further graph of a proportional band.

Describing now the drawings, from the showing of Fig. 1 it will be apparent that a comparator 10 of a primary or main regulation circuit, has infed thereto, by means of a line or conductor 12, a reference value Xk of the room temperature which has been set at a schematically illustrated conventional reference value transmitter 11. Furthermore, there is infed to the comparator 10, by means of a line or conductor 14, a signal of a temperature-actual value which is delivered by a room temperature feeler or sensor 16. The output signal of the comparator 1 0, which corresponds to the difference between the reference value Xk and the actual value, is infed by means of a line 18 to a first amplifier 20.The amplified output signal of the amplifier 20 is delivered, by means of a line or conductor 22, as a control input or signal to a second comparator 24 for an auxiliary regulation cir cuit. Moreover, there is delivered to the sec ond comparator 24, by means of a line or conductor 26, the signal of the air volume or quantity-actual value of an air qantity or air velocity feeler 28.

The output signal of the second comparator 24 arrives, by means of a line or conductor 30, at the input or input side 32a of a limiter and influencing device 32, hereinafter simply referred to as a limiter or limiting device. The limiter 32 possesses an adjustment or setting element 34 for a minimum threshold value or threshold and a further adjustment or setting element 36 for a maximum threshold value or threshold. The limiter 32 contains, for in stance, standard Wheatstone bridge means and amplifier means, for instance a bridge amplifier as generally indicated by reference character 32b, coacting with the setting ele ments 34, 36.By means of the terminals 38 and 50 it is possible, by means of a positive control, constituted for instance by the switches 39 and 41, to accomplish falling below or exceeding the threshold values which have been set at the adjustment or setting elements 34 and 36 respectively, so that the regulation system has a regulation characteristic 60 which includes the portions 39' and/or 41', as the case may be, as shown in Fig. 2. In practice, the circuit configuration can be designed such that the first comparator 10 and first amplifier 20 are com bined into a unit, while the the second com parator 24 and the limiter 32 are likewise combined into another unit.

The output signal of the limiter 32 is infed by means of a line or conductor 42 to a second amplifier 44 and, following its amplifi cation, serves as the adjustment or setting signal which is delivered, by means of a line or conductor 46, to an adjustment or setting element 48 for instance a flap valve controlled by a suitable drive 49. Instead of using just one adjustment element 48 it is possible to connect in parallel with the adjustment ele ment 48 also further adjustment or setting elements, which conjointly effect the air quan tity or volume which is infed to the room which is to be ventilated or climatized. The air quantity or the corresponding air velocity which flows per unit of time is measured by the previously mentioned air quantity or vol ume feeler 28. Reference character 50 desig nates the first regulation path i.e. the path defined by an air duct or channel extending between the control flap valve 48 and the air volume feeler 28, which is operatively corre lated with the air quantity-regulation circuit.

The second regulation path, operatively as sociated with the temperature regulation cir cuit, has been designated by reference charac ter 52. The second regulation path 52, embodying the room or area to be climatized, extends up to the previously discussed room temperature feeler or sensor 1 6.

The primary regulation circuit, correlated to the temperature regulation, encompasses the elements 10, 18, 20, 22, 24, 30, 32, 42, 44, 46, 50, 28, 52, 16 and 14.

The auxiliary regulation circuit, correlated with the air volume or quantity regulation, is integrated in the primary regulation circuit and encompasses the elements 24, 30, 32, 42, 44, 46, 50, 28 and 26.

From the illustration it will be apparent that the primary regulation circuit and the auxiliary regulation circuit constitute closed regulation circuits or loops.

Turning attention now to Fig. 2, along the abscissa of the therein illustrated graph there has been plotted the room temperature t. The air quantity Q has been plotted along the ordinate between 0o and 0100%. Between the values 0 and 100% there are illustrated the minimum threshold Qmin and the maximum threshold Qm,x, which can be adjusted at the adjustment or setting elements 34 and 36 of the limiter or limiting device 32 (Fig. 1).

Reference character Xk constitutes the reference or set value for the temperature regulation which has been plotted along the abscissa. This reference or set value Xk is infed to the comparator 10 (Fig. 1) of the primary regulation circuit. Reference character Xp designates the proportional band, which in the indicated exemplary embodiment under discussion is symmetrically dispositioned with respect to the reference value Xk. The proportional band Xp extends in its width over a predetermined region or range of the temperature scale t.From the illustration of Fig. 2 it will be further apparent that the proportional band Xp always assumes the same width at the temperature scale t between the air volumes or quantities Qo and 0100% (regulation characteristic 62) and equally between the threshold values Qin and Qmax (regulation characteristic 60). In order to fulfil such requirement it is necessary that the regulation characteristic of the proportional band Xp change its slope, if such proportional band should retain the same width independent of the settings of the threshold values 0mien and Oman. This requirement can be fulfilled with the teachings of the present invention.In particular, the proportional band Xp is governed by both thresholds, here for instance Qmln and Qmax and the slope of the regulation characteristic, here the characteristic 60, and which slope, in turn, is governed by the influence of the aforedescribed primary temperature regulation circuit and the air quantity-auxiliary regulation circuit. Upon changing of either the upper threshold Qmax and/or Qmin there is adjusted the influence of the air quantity-auxiliary regulation circuit, and, in turn, there is correspondingly altered the slope of the characteristic so that the width of the proportional band Xp remains unaltered.

For instance, when changing the values of Qmin and Qmax to Q0 and Q100OG, respectively, there is realized, instead of the regulation characteristic 60, a regulation characteristic 62 of steeper slope, while the proportional band Xp remains constant in width, as shown.

In Fig. 3 there has been shown, in contrast to the illustration of Fig. 2, additionally a proportional band Xp2, which corresponds to an arrangement wherein the slope of the proportional band only is changed upon altering the upper threshold value Qmax On the other hand, altering the lower threshold value Qmin does not influence the slope or inclination of the proportional band.

Since there has always been selected as the minimum air quantity as small as possible proportion, it is sufficient if the proportional band Xp2 only is effected upon adjustment of the upper threshold value Qmax The deviation between the entire proportional band Xp and the effective proportional band Xp2 is generally smaller than 25%, so that there does not arise any instability during the regulation and such can be effectively controlled.

From the showing of Figs. 2 and 3 there will be apparent the characteristic of the entire regulation circuit illustrated in Fig. 1. If the measured room temperature t deviates from the reference or set value Xk then the regulator adjusts the air quantity or volume Q between the thresholds or threshold values Qmin and Qmax in accordance with the illustrated proportional band Xp and Xp2, respectively.If by means of the terminals or connections 38 or 40, by controlling the limiter 32, there is fallen below or exceeded the thresholds Qmin or Qmax, then the regulator can adjust the air quantity depending upon its task, either to Qo or to 0100%. The air quantity Qo is then selected whenever the room which is to be ventilated or climatized is not occupied or if a window or door is open for ventilation purposes. To this end, it is possible to arrange at the door or at the window an electrical contact or equivalent structure which acts upon the regulator. The full air quantity Q100oKo then can be adjusted, for instance by means of a handswitch, if a room, such as an auditorium or conference hall, should be ventilated with the largest available air volume or quantity during a pause in the activities within such auditorium or conference room, in other words thre is carried out a so-called surge ventilation.

Claims (10)

1. A method of regulating an air ventilation or air climatizing apparatus, comprising the steps of infeeding a signal of a primary regulation circuit as a control signal to an air quantity-auxiliary regulation circuit, in order proportionally to influence the quantity of air which is supplied to a room which is to be ventilated or climatized, as a function of a regulation magnitude of the primary regulation circuit, preselecting for the supplied quantity of air a lower threshold and an upper threshold, and maintaining the position of at least that side of a proportional band, operatively correlated with the upper preselected threshold, independently of the upper preselected threshold.

2. A method as claimed in claim 1, including the steps of utilizing as the regulation magnitude of the primary regulation circuit the temperature of the room which is to be ventilated or climatized.

3. A method as claimed in claim 1 or 2, including the steps of utilizing, as the air which is supplied to the room, cool air, and increasing the quantity of air with increasing rooom temperature.

4. Apparatus for regulating an air ventilation or air climatizing installation, comprising a primary regulation circuit including a first comparator having a first input arranged to receive a signal representative of a preselected temperature reference value and a second input connected to receive a signal from temperature sensitive means which measures the actual value of the room temperature to be regulated, an air quantity-auxiliary regulation circuit including a second comparator having a first input connected to the output of the first comparator and a second input connected to an air sensor for supplying thereto a signal representing the actual value of the air quantity measured by the air sensor, an adjustment element for adjusting the air quantity supplied to the room, limiter means connecting the output of the second comparator to the adjustment element, said limiter means being provided with adjustment elements for a lower threshold and an upper threshold, and at least the adjustment element for the upper threshold being connected with means for determining a proportional band, in order to influence independently of the upper preselected threshold value the position of a side of the proprtional band which is correlated with the upper threshold value during adjustment of such upper threshold value.

5. Apparatus as claimed in claim 4, including bridging element means for enabling falling below or exceeding one or the other of said threshold values which are set by the adjustment elements.

6. Apparatus as claimed in claim 5, wherein the bridging element means is connected to terminal means in order to control switch means located externally of the regulation circuit.

7. Apparatus as claimed in claims 4, 5, or 6 wherein the air sensor is an air quantity sensor.

8. Apparatus as claimed in claims 4, 5 or 6 wherein the air sensor is an air velocity sensor.

9. Apparatus for regulating an air ventilation or air climatizing installation, constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

10. A method of regulating an air ventilation or air climatizing apparatus, substantially as hereinbefore described with reference to accompanying drawings.