JPS6361575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a closed piping system for cold and hot water for air conditioning in buildings.

This system uses a closed pressure tank to convert expansion and contraction due to temperature changes in cold and hot water circulating between a heat source device that cools or heats water, which is a heat medium, and a load device such as a fan coil unit, into internal pressure changes. Because the water is absorbed, the cold and hot water never comes into contact with the atmosphere, and new water is not replenished except in special cases. The reason for this sealed piping structure is that when cold and hot water comes into contact with the atmosphere or when new water is replenished, new oxygen dissolves into the cold and hot water, and this reacts with the pipes as it circulates through the pipes. This is because it causes rust and shortens its durable life.

By the way, even in sealed piping like this, air has been dissolved in the cold and hot water that has existed since the beginning.
It circulates without being separated in a steam separator,
This causes air bubbles to accumulate at the highest point during circulation, such as the elbow of torii piping or the upper part of the coil of a rising type load device. As a result, there are problems such as generation of abnormal noise in the load equipment and reduction in heat exchange efficiency. For this reason, air vent valves are currently provided at locations where air bubbles accumulate, such as the elbow portion and the upper part of the coil in the fan coil unit. However, when air is vented using such an air vent valve, air from the atmosphere may enter the interior due to negative pressure inside, and as a result, air bubbles often accumulate. The disadvantage is that the advantages of the closed type are completely lost as new oxygen is dissolved in the cold and hot water.

Therefore, the present invention eliminates the air vent valve of the load equipment, eliminates air intake from the air vent valve, maintains dissolved oxygen in cold and hot water at a low concentration, and effectively prevents corrosion in various parts of the system. This prevents abnormalities from occurring or the heat exchange rate from decreasing due to air bubbles staying at the top of the coil, etc., and also ensures economic efficiency by preventing the flow rate of hot and cold water from becoming faster than necessary during normal times. This provides a new means for doing so.

Hereinafter, one embodiment of the present invention will be described based on the drawings. In Figure 1, 1 is a heat source device that cools or warms water, which is a heat medium, by an indirect heat exchange method (this may be either a cooler or a heater, and a cooler and a heater are installed). (2) may be configured to be used alternatively as necessary, or may be configured to have both functions and switch between the cooling function and heating function as necessary. In this embodiment, as shown in FIGS. 2 and 3, a vertical tube 2a and a cold/hot water stream tangentially connected to the vertical tube 2a are used. An inlet pipe 2b, a cold and hot water outlet pipe 2c,
A cyclone type steam/water separator is used, which is equipped with a bubble discharge pipe 2d that is connected to the center of the upper end of the vertical cylinder 2a. 3 is a variable pump for circulating hot and cold water. These three are connected in series by a main pipe 4. 5... is a load device such as a fan coil unit that heats or cools the air in each room of the building by indirect heat exchange method, and connects the piping 7 to the series circuit via the supply header SH and the return header RH. ...connected by... This piping 7
In this embodiment, a pipe with a diameter of 15 mm is used, and a pipe with a diameter of 25 mm is used as the main pipe 4. 8 is a closed pressure tank, and a bubble discharge pipe 2d is connected to the steam separator 2.
connected via. It is desirable that the tank 8 and the steam separator 2 be housed in one frame 9 to form a unit, as shown in FIGS. In the figure, 10 is a safety valve, 11 is a water level adjustment pot, 12 is a water supply device, pressure reducing valve 13, pressure gauge 14, check valve 1
5. It consists of a strainer 16. This water supply device 12 is used only when it is particularly necessary, such as when initially supplying water into the system or when the water level in the tank becomes extremely low due to a malfunction or the like, and is not normally used.

In the above configuration, in this embodiment, a part 4a where air bubbles in cold and hot water tend to accumulate is provided in a part of the series circuit, for example, between the steam separator 2 and the variable pump 3. A bubble detector 17 is provided, and based on the detection results of the bubble detector 17, when there are bubbles, the flow rate of cold and hot water flowing through the main pipe 4 is 0.6 m/sec or more, and when there are no bubbles, it is less than 0.6 m/sec. The variable pump 3 is configured to be controlled to achieve a slow economical speed.

In addition, as the above-mentioned portion 4a where air bubbles tend to accumulate, the elbow portion etc. of the main pipe 4 may be used as is, and if there is no suitable elbow portion etc. near the variable pump 3, the said portion 4a may be actively used. It is set up in a specific manner. In other words, air bubbles accumulate before they accumulate in areas where air bubbles tend to accumulate, such as the torii piping part and elbow part of the main pipe 4, the torii piping part that connects the load equipment 5, and the upper part of the coil inside the load equipment 5. Alternatively, a dummy elbow portion 4a, a coiled bent pipe, or the like may be provided in each of the above portions, where air bubbles may be retained. As the bubble detector 17, for example, a current meter using ultrasonic waves can be used.

According to the above configuration, if there are bubbles in the cold/hot water, the bubble detector 17 detects the bubbles and increases the flow rate of the cold/hot water, so that Air bubbles accumulated at the upper end of the coil etc. can be washed away together with cold and hot water, and as a result, various inconveniences caused by the accumulation of air bubbles can be avoided, and the load equipment 5...
There is no need to install an air vent valve in the system, there is no need for atmospheric air to be sucked in through the air vent valve, and there is no increase in dissolved oxygen concentration due to this, and corrosion of various parts of the system can be reliably prevented for many years. In normal times when there are no air bubbles, cold and hot water flows at an economical speed, making it possible to reduce operating costs and extend the life of pumps and the like.

The critical significance of setting the flow velocity to 0.6 m/sec or higher was confirmed through experiments. In other words, we varied the flow velocity and examined whether the stagnant air would start to move at each flow velocity. Figure 4 shows the experimental results.
As is clear from the figure, at 0.6 m/sec or less, there is almost no movement, and at 0.6 m/sec or more, the speed of air movement increases in proportion to the flow velocity. from this result,
It was confirmed that a flow velocity of 0.6 m/sec or higher is required. However, in reality, it is desirable to set the speed to an appropriate speed of 0.6 m/sec or more in relation to the time required to remove the accumulated air. When a large amount of air enters the piping system, such as when starting the system by supplying air, the flow velocity should be faster than when air is removed during operation, usually about 1.0 m/sec.

It should be noted that the flow velocity does not need to be maintained at the above speed all the time; it is sufficient to maintain it for a certain period of time when air accumulates in the elbow, etc., and such a configuration is advantageous in terms of economy. It is. Therefore, in the present invention, the flow rate is made variable as described above, and is changed based on the detection result of the bubble detector 17.

As explained above, the air-conditioning cold/hot water sealed piping system for buildings according to the present invention includes an indirect heat exchange type heat source device, a steam separator, and a variable pump for cold/hot water circulation connected in series through a main pipe, and this series circuit. A part of the series circuit includes an indirect heat exchange type load device connected by piping to the steam separator, and a closed pressure tank connected to or integrated with the steam separator. A part where air bubbles tend to accumulate is provided, a bubble detector is provided in this part, and the variable pump is controlled based on the detection result of this air bubble detector, so that if there are air bubbles in the part, the variable pump is controlled. In order to increase the flow rate of cold and hot water, the air bubbles can be washed away and discharged into the closed pressure tank through the steam separator, and if there are no air bubbles,
Economic efficiency can be ensured by slowing down the flow velocity. Therefore, even if the air bleed valve of the load equipment is omitted, it is possible to prevent air bubbles from accumulating in the upper part of the coil of the load equipment, causing abnormal noise and reducing heat exchange efficiency. Since suction is eliminated and the dissolved oxygen concentration in cold and hot water can be lowered, corrosion of various parts of the system can be prevented and the durability life can be dramatically extended. The combination of slowing down, eliminating the need for an air vent valve, extending the service life, etc. all make it possible to ensure overall economic efficiency.

[Brief explanation of drawings]

The figures show an embodiment of the present invention; FIG. 1 is an overall piping configuration diagram showing an embodiment of the present invention; FIG. 2 is a front view of a configuration in which a steam separator and a tank are integrated;
FIG. 3 is a top view of the second one, and FIG. 4 is experimental data showing the relationship between flow velocity and air removal time. 1...Heat source equipment, 2...Steam water separator, 3...Variable pump, 4...Main pipe, 4a...Part where air bubbles tend to accumulate,
17...Bubble detector.

Claims (1)

[Claims] 1. Indirect heat exchange type heat source equipment, a steam/water separator, and a variable pump for circulating hot and cold water connected in series through a main pipe, and one or more indirect heat sources connected to this series circuit through piping. It comprises a replaceable load device and a closed pressure tank connected to or integrated with the steam separator, and a part of the series circuit is provided with a part where air bubbles in the cold and hot water tend to accumulate. A closed piping system for cold and hot water for air conditioning in a building, characterized in that a bubble detector is provided in this part, and the variable pump is controlled based on the detection result of the bubble detector. 2 The variable pump is controlled such that the flow velocity in the main pipe is 0.6 m/sec or more when there are bubbles in the cold and hot water, and the flow velocity in the main pipe is slower than 0.6 m/sec when there are no bubbles in the cold and hot water. 2. The system according to claim 1, wherein the system is controlled so that: