JPH06193918A - Heat storage tank - Google Patents

Abstract

PURPOSE:To ensure the detection of the completion in the cold storage of emulsion by detecting changes in the density of an emulsion cold heat storage material attributed to emulsion phase transformation and emulsion water evaporation by an ultrasonic wave to be transmitted from an ultrasonic transmission element. CONSTITUTION:Changes in the density of an emulsion cold heat storage material 3 attributed to emulsion phase transformation at about 0-5 deg.C and emulsion water evaporation above 50 deg.C are detected by an ultrasonic wave to be transmitted from an ultrasonic transmission element 4. A heat storage tank 1 is made of material accompanying neither denaturation nor corrosion to paraffin emulsion. A heat source of an emulsion cold heat storage device 2 herein used is a heat pump in general. The cold heat storage material 3 is a dispersion of wax of fat, paraffin or the like and water. The ultrasonic transmission element 4 is set contacting any one of water contact surfaces of the cold heat storage material 3 evenly. Thus, the detection of cold storage and evaporation of the emulsion cold heat storage material 3 is accomplished with the same sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for detecting a state change of a cold storage heat material in a cold storage heat air conditioning system.

[0002]

2. Description of the Related Art Two types of conventional cold storage systems are known: ice cold storage for making ice in a tank and cold storage, and water cold storage for storing cold water in the tank. However, the tank itself became large (water cold storage), and the tank cost became large (ice cold storage).

Therefore, the inventors of the present invention disclosed in Japanese Unexamined Patent Publication No. 4-222894.
As shown in No. 6, if the cold storage heat material that can utilize latent heat such as paraffin emulsion is used for the cooling storage medium and the cooling medium is directly cooled and transported, the system itself can be downsized and the cost can be reduced. Devised.

The emulsion does not solidify even when the paraffin undergoes phase transformation. Therefore, it is possible to store cold while always flowing. As a result, a large-scale heat exchanger such as an ice system is not necessary, and the emulsion can be stored while convection of the surrounding emulsion with a very small heat exchanger.

The end of cold storage of the emulsion is confirmed, for example, when the emulsion temperature in the entire heat storage tank reaches the emulsion melting point (3 to 5 ° C. in the case of paraffin). For this, temperature sensors (thermocouples / thermistors etc) installed at a plurality of locations in the tank are used.

[0006]

However, in the cold storage completion detection using the emulsion depending on the temperature, it is difficult to grasp the complete end time because the temperature change of the emulsion (cold heat storage material) during the phase transformation shows a constant value. Therefore, it is the current situation that a little further supercooling is performed to confirm the cold storage. In addition, the temperature distribution inside the tank during cold storage detection is often not constant due to the fact that the emulsion cold storage heat material is a viscous fluid (especially the viscosity of the emulsion cold storage heat material during cold storage is high), so try to detect the end accurately. If you think about it, the number of temperature sensors increases and the efficiency is poor.

Further, when the emulsion cold storage material is used as a high temperature sensible heat storage material for heating, the water in the emulsion starts to evaporate at a temperature of 50 ° C. or higher. Evaporation of water in the emulsion not only affects the stability (uniform dispersion, uniform concentration) of the cold storage heat material, but may increase the paraffin concentration in the emulsion and change it into a dangerous substance. In order to avoid this, it is necessary to detect the water surface of the heat storage tank with a float switch or the like and feed back the evaporation amount to the water supply tank.

[0008]

The gist of the present invention consists of a cold storage material using an emulsion composed of paraffin, water, a surfactant, etc., an ultrasonic wave transmitting element, and an ultrasonic wave reflecting plate. In the heat storage tank of the emulsion cold storage system, the emulsion phase transformation around 0 to 5 ° C and the density change of the emulsion cold storage material due to emulsion water evaporation at 50 ° C or higher are detected by the ultrasonic waves transmitted from the ultrasonic wave transmission element It is a heat storage tank characterized by that.

[0009]

[Operation] Ultrasonic transmitter 4 installed in heat storage tank 1
The ultrasonic waves transmitted from the above are reflected by the reflection plate 5 installed above the tank 1, and the reflected wave is measured.

If the reflected wave characteristics of the emulsion before the phase transformation and the reflected wave characteristics after the phase transformation are known in advance, the reflected wave characteristics change from before the phase transformation to after the phase transformation during cold storage. When the wave characteristics converge to the values after the phase transformation, the cold storage can be completed there. In addition, if the reflected wave characteristics at high temperature change in some way from before the phase transformation, it can be determined that water has evaporated and water can be supplied.
In order to avoid erroneous judgment, it is better to understand the relationship between the paraffin concentration and the reflected wave characteristic when the water gradually evaporates and the paraffin concentration in the emulsion rises.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. The present invention will be disclosed based on this figure.

Reference numeral 1 denotes a heat storage tank, which is made of a material that does not cause denaturation or corrosion of paraffin emulsion. For example, FRP that has no rust and is resistant to emulsion corrosion
Etc. would be appropriate.

Reference numeral 2 is an emulsion cold heat storage device, and a heat pump is generally used as its heat source.

Reference numeral 3 is a cold storage material using an emulsion, which is a dispersion of wax such as fats and oils and paraffin and water. It goes without saying that the surfactant and the antifreezing agent for stabilizing the dispersion are mixed in the emulsion. The above is the same as the conventional emulsion cold storage system.

Reference numeral 4 is an ultrasonic wave transmitter. Since the ultrasonic waves have a straight traveling property, it will be effective to install the cold storage material 3 so that it uniformly contacts any one of the water contact surfaces. In this embodiment, the ultrasonic transmitter 4 is attached to the inner surface of the bottom, and the ultrasonic reflector 5 is provided so as to be in contact with the liquid surface and face the ultrasonic transmitter 4.

Since the frequency band of ultrasonic waves has a strong directivity and it is desired to prevent cavitation (the reflected wave characteristics differ when cavitation occurs), 1 MHz or more is preferable. Further, the transmitted wave is preferably a pulse wave. This is to prevent the transmitted wave and the reflected wave from being mixed. A crystal oscillator, a barium titanate-based porcelain oscillator, or the like, which can use a high frequency band, is preferable as the transmitter.

[0017]

According to the present invention, it is possible to provide a cold storage heat tank which can detect cold storage and evaporation of a cold storage material using an emulsion by the same sensor.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of the present invention.

[Explanation of symbols]

 1 Heat Storage Tank 2 Cold Storage Heat Source 3 Emulsion Cold Storage Material 4 Ultrasonic Transmitter 5 Ultrasonic Reflector

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiki Tamura 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Noriyuki Kitachi, 1048, Kadoma, Kadoma City, Osaka Matsushita Electric Co., Ltd.

Claims (1)

[Claims] 1. A heat storage tank of an emulsion heat storage system comprising a cold heat storage material using an emulsion composed of paraffin, water, a surfactant, etc., an ultrasonic wave transmission element, and an ultrasonic reflection plate, and 0 to 5 °. A heat storage tank characterized by detecting the phase change of emulsion around C and the density change of emulsion cold storage material due to evaporation of emulsion water at 50 ° C or higher by ultrasonic waves transmitted from an ultrasonic wave transmission element.