JPH0446533B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention relates to a multi-stage variable temperature control method for a hot water heating system in a greenhouse for greenhouse horticulture, more specifically, a method for controlling a hot water heating system in a greenhouse for greenhouse horticulture, a chicken house, a livestock barn, etc. This invention relates to a multi-stage variable temperature control method.

(2) Background of the technology In greenhouse horticulture, it is important to actively manage temperature in accordance with the ecology of the crops. In addition, temperature control is required in the early stages of chick growth in a poultry house, and it is known that, for example, in growing pigs, favorable results can be obtained if temperature control is performed during feeding. In other words, in the raising of chickens and other livestock, it is becoming more and more common to control the temperature during sleep, during daytime activities, when feeding, etc. Such temperature control is performed, for example, by operating a heater using a boiler or utilizing solar heat by a solar system.

However, when using a solar system, the heating effect depends on the weather, and when using a heater, considering the increase in the cost of oil and electricity, which is the main energy source, and the complexity of operation management, heating efficiency is more important than heating efficiency. Technology development is being strongly promoted to achieve this goal.

(3) Conventional technology and problems Conventionally, heating in greenhouses for greenhouse horticulture using boilers, for example, involves installing radiant pipes or heat exchangers inside the greenhouse, and connecting these to the boiler with piping to connect hot water. Systems that perform hot water radiation heating using natural convection or forced draft through heat exchange, or heating systems that perform heating by burying pipes underground and flowing hot water through these pipes have been put into practical use.

In the above-mentioned heating system, the boiler is adjusted according to the heating load (the difference between the outside temperature θ _p and the indoor control temperature θ _r ; when the difference is large, the load is heavy, and when the difference is small, the load is light). In other words, the heating effect is improved by setting the hot water temperature higher when the load is heavy and lower when the load is light.
The setting of the hot water temperature is automatically performed using a boiler load control device equipped with a load setting means.

Figure 1 is a circuit diagram of the main parts of a conventional load control device.
Figure a shows a temperature sensor signal detection section, and Figure b shows a hot water set temperature calculation section, and the control circuit is formed of a power supply section and other auxiliary circuits in addition to the above two circuit sections. In FIG. 1b, 2 is a boiler, 10 is a radiator, such as a heat exchange type heater,
LC indicates a limit circuit, and such a device is the original invention (Patent Application No. 71525 of 1982, Japanese Patent Publication No. 2-49685)
It was disclosed in Here, assuming that the greenhouse control temperature θ _r , the outside air temperature θ _p and the boiler hot water set temperature θ _w are, as mentioned above, the boiler hot water temperature should be set according to the heating load, that is, when the load is heavy, θ The heating effect can be improved by setting _w higher, or lower if it is lighter, so the relationship (θ _w − θ _r )/(θ _r − θ _p )≡α ...(1) By setting certain heating load factors α and θ _r to variable resistors (hereinafter referred to as volumes) VR2 and VR1 shown in FIG. 1, the boiler set temperature θ _w is automatically determined and the boiler is operated.

The control device can also operate the radiator at the same time as the boiler (see Figure 2). In Figure 1, T _r , T _p , and T _w are thermistors for detecting the greenhouse temperature, outside air temperature, and boiler hot water temperature, respectively (the detected temperatures are given to outputs A, B, and D in Figure a, respectively). ), R1 to R17 are resistors, IC1
~IC7 is a comparator, Q1 and Q2 are transistors, R _y 1 and R _y 2 are relays, and the limit circuit LC is such that the calculated hot water set temperature θ _w is
This circuit determines whether the boiler is within the safe operating temperature range.

Fig. 2 is a device configuration diagram of a heating system using the conventional load control device described above, in which 1 is the load control device, 2 is a fully automatic hot water boiler, 5 is a circulation pump, 6 is a hot water supply pipe, 10 indicates a radiator, such as a heat exchange type heater.

The load control device 1 transmits operation information to a signal line 4 from input information from a hot water sensor 3, an outside temperature sensor 7, and an indoor temperature sensor 8 arranged in the boiler 2, and the set values of the management temperature and heating load factor described above.
It is applied to the boiler 2 by the signal line 9 and to the heater 10 by the signal line 9. Note that the on/off of the circulation pump 5 that sends hot water to the heater 10 can be controlled in conjunction with the on/off of the radiator 10.

By the way, in greenhouses for greenhouse horticulture, for example, in addition to constant temperature control that maintains the temperature inside the greenhouse constant throughout the day using the methods and devices described above, variable temperature control that changes the controlled temperature over time is required.

This variable-temperature management has the advantage of creating an optimal environment for plant growth and at the same time eliminating unnecessary energy consumption and saving costs. A control device that can change the greenhouse temperature in stages is required. However, since the conventional load control device described above maintains the indoor temperature setting constant throughout the day, it is not only impossible to perform variable temperature control over time as described above, but also prevents heating when it is not needed. There is a problem that energy such as oil and electricity is wasted by doing this.

(4) Purpose of the Invention In view of the above-mentioned conventional problems in implementing the original invention, an object of the present invention is to provide a multi-stage variable temperature control method that can automatically change indoor temperature control in stages as time passes.

(5) Structure of the Invention According to the present invention, the purpose is to provide a method for controlling a hot water heating system in a greenhouse for greenhouse horticulture, in which the boiler hot water set temperature is θ _w , the indoor control temperature is θ _r , and the outside air temperature is θ _p Assuming that the boiler hot water setting upper limit temperature is θ _wh and the outside air temperature minimum temperature is θ _p l, for α given by the following equation (θ _wh −θ _r )/(θ _r −θ _p l)=α, (θ The relationship between _w - θ _r ) and (θ _r - θ _p ) satisfies the following equation (θ _w - θ _r )/(θ _r - θ _p ) = α, and θ _w is at the boiler safe operating temperature. In implementing the control method to set the value within the range defined by the upper limit value θ _wh and the lower limit value θ _w l, the outside air temperature θ _p , the boiler hot water setting upper limit temperature θ _wh and the outside air temperature minimum temperature θ _p l are set. In addition, the indoor control temperature θ _r
Set multiple values, and adjust the indoor control temperature θ _r as time passes.
A hot water heating system for a greenhouse for greenhouse horticulture, characterized in that one of them is selected in a desired order, and the boiler hot water set temperature θ _w is automatically changed in multiple steps according to the selected indoor control temperature. This is achieved by providing a multi-stage variable temperature control method.

(6) Embodiments of the Invention Examples of the present invention will be explained below using an example of a four-stage temperature change system with reference to the drawings.

Figure 3 shows an indoor control temperature setting circuit in a four-stage variable temperature load control circuit. Referring to the figure, four volumes VR3, VR4, VR5, and VR6 are arranged in parallel, and each has four levels of indoor control temperature θ. Set _r . On the other hand, the volume can be changed by, for example, arranging a program timer TM and switching the switches t1 to t4 of the relay circuit in a desired order. In the past, boilers were operated using only VR1 and VR2 to keep the internal temperature constant at all times (single-stage type), but as mentioned above, multiple variable resistors (volumes) were installed, and each one was used to control heating. By setting the load factor and combining these volumes with a timer, the boiler can be operated to provide the necessary heating economically.

In agricultural greenhouse cultivation, the 24 hours a day are divided into four time periods: early morning, daytime, diversion, and night, and there are management temperatures suitable for each time zone.For example, diversion, which increases plant respiration, There is a characteristic that the control temperature can be set high during certain times of the day and lower during other times. For this reason, rather than keeping the temperature constant 24 hours a day, it is more effective to save energy by dividing the temperature into four stages.

When introducing a load controller into a house heated using a boiler, the above method can be used for multi-stage temperature change,
For example, it is necessary to set θ _r using a plurality of variable resistors.

For example, when the switch is switched to t3 at a certain time, the relay Rθ _y 5 is activated, so that the relay switch s5 is closed, and the voltage corresponding to the temperature set at the volume VR5 is shown in FIGS. 1 and 2. It is given as an output C, and the operation of the boiler 2 is controlled. In the other switches, a voltage corresponding to the set temperature is similarly given as the output C.

The circuit is also equipped with a display circuit that indicates which temperature setting is set for ease of operation. Such a display circuit includes light emitting diodes L1 to L.
It consists of 4 parallel circuits, and the relay circuit switches t1 to t4 are controlled by the program timer TM.
The switches t1' to t4' are switched in conjunction with the switching of the switches t1' to t4'. By switching the switches t1' to t4', a light emitting diode corresponding to the set temperature emits light, making it easy to confirm the set control temperature. In the same figure, R21 to R28 are resistors and D
1 to D2 indicate diodes, voltages V and Vcc are given from a separately provided power supply circuit (not shown), and G
is given a ground potential.

The indoor control temperature setting circuit described above can be used in place of the volume VR1 to provide the output C of the circuit shown in FIG. By configuring the heating system shown in the figure, highly accurate multi-stage variable temperature heating can be achieved.

In addition, in this embodiment, the control temperature is set to 4.
It is carried out in stages, but depending on the purpose, for example 3
A stage or five stage circuit can be configured, and the range of application of the load control device can be expanded. Therefore, it can be used not only in greenhouses for greenhouse horticulture, but also in chicken houses, livestock houses, etc.

(7) Effects of the Invention As explained in detail above, according to the present invention, the control temperature can be automatically changed in stages according to the purpose, and the boiler can be automatically operated in an appropriate manner according to the heating load. Since variable temperature control is possible, a more advanced temperature management system can be realized, and
Efficient operation of the boiler is effective in saving energy.

4 Additional Relationships The present invention provides, in the load control method of the original invention, that the indoor control temperature setting means of the control method is a multi-stage type capable of setting a plurality of temperatures from a single-stage type, and at the same time, the set temperature is automatically changed by a timer. It is characterized by its ability to be applied to more complex temperature control.

Fig. 4 is a diagram showing the mode of high-precision temperature control of the load control device, in which a shows the conventional temperature control method (hot water set temperature 80°C, control temperature 29°C), and b shows the load control method according to the present invention. (Load factor α = 1.8, control temperature 33
These are the measurement results for temperature control (°C). In the figure, the horizontal axis represents elapsed time, and the vertical axis represents temperature deviation, that is, the difference between the set temperature and the measured temperature.

Referring to the figure, the heating system using the negative coefficient control method can achieve the desired indoor temperature with less temperature deviation than the conventional heating system. The above results can be achieved by temperature control of each set temperature in a multi-stage system, so the present invention can easily achieve high-precision variable temperature control, and also improves the efficiency of the boiler compared to the original invention. This enables efficient operation and further improves energy savings.

[Brief explanation of the drawing]

Figures 1a and b are circuit diagrams of the main parts of a conventional load control device, and Figure 2 is a device configuration diagram of a conventional heating system.
Figure 3 is a multi-stage management temperature setting circuit diagram of the present invention;
Figures a and b are diagrams showing the measurement results of temperature deviation, where figure a is a diagram for the conventional example, and figure b is a diagram for the case according to the present invention. 1...Load control device, 2...Boiler, 3,
7, 8...Temperature sensor, 5...Circulation pump,
4, 9...Signal line, 10...Heater, IC1~IC
5... Operational amplifier, IC6, IC7... Comparator, R1 to R28... Resistor, VR1 to VR6...
Temperature setting volume, R _y 1 to _{R y} 6...Relay,
Q1, Q2...transistor, LC...limit circuit.

Claims (1)

[Claims] 1. A method for controlling a hot water heating system in a greenhouse for greenhouse horticulture, in which the boiler hot water setting greenhouse is θ _w , the indoor control temperature is θ _r , the outside air greenhouse is θ _p , and the boiler hot water setting upper limit temperature is For α given by the following equation (θ _wh −θ _r )/(θ _r −θ _p l)=α, where θ _wh and the minimum outside temperature θ _p l, (θ _w −θ _r ) and (θ _r −θ _p ) satisfies the following equation (θ _w −θ _r )/(θ _r −θ _p )=α, and θ _w is the upper limit θ _wh and lower limit θ _w of the boiler safe operating temperature. In carrying out the control method to set the value within the range defined by l, in addition to setting the outside air temperature θ _p , boiler hot water setting upper limit temperature θ _wh and outside air temperature minimum temperature θ _p l, the indoor control temperature θ _r
Set multiple values, and adjust the indoor control temperature θ _r as time passes.
A hot water heating system for a greenhouse for greenhouse horticulture, characterized in that one of them is selected in a desired order, and the boiler hot water set temperature θ _w is automatically changed in multiple steps according to the selected indoor control temperature. Multi-stage variable temperature control method.