FI117647B - Antifreeze for heat recovery installations - Google Patents

Description

The present invention relates to an antifreeze device for heat recovery plants.

5 Heat recovery units designed according to the transverse flow principle normally use hot exhaust air, or the indoor air passes through a heat exchanger cassette with multiple plate channels. Cold outdoor air or feed air passes through the respective heat exchanger group in the same heat exchanger. The heat exchanger cartridge is generally rectangular in cross-section and the exhaust air ducts and supply air ducts are arranged alternately in succession at a distance from each other.

The duct walls of the heat exchanger cartridge are made of normal-15 thin aluminum, for example 0.1 mm. In this case heat is transferred from one side to the other through the plate side very quickly and easily. Normal air velocities in the ducts are 1.5 m / s and the thermal efficiency can be about 60%.

20 Under various moth conditions between exhaust air and outdoor air, ice may form in the exhaust air ducts of the heat exchanger, which can significantly increase and possibly block the open surface area of the ducts. Such -u; · *.

. . ·. the situation usually occurs when the outdoor temperature is • * · 25 about -8 ° C and the relative humidity of the extract air is above 28%.

"*! The exhaust air temperature is approximately 20 ° C. Various measures have been developed to prevent ice formation and the exhaust air ducts. With the thermostat, the outdoor air blower can be stopped when the air temperature of the exhaust air duct 30 is reached. below a certain level, and restart when the temperature is at an acceptable level, and. ·., preheating can be started when the thermostat indicates, · * that the exhaust air temperature has fallen below a predetermined level. that such solutions are combined, preferably in two phases. In addition, the temperature f • · 2 117647 detector can register the pressure drop that can occur when ice builds up in the system, and the timer relay will reset the normal operation of the unit when the ice has thawed.

5 For the first three possibilities, the shut-off function is not required when the exhaust air is dry, which is normal even on cold winter days. Therefore, the outdoor fan should operate normally in such cases and achieve the desired, necessary ventilation balance.

For the latter option, monitoring the exhaust fan speed is difficult and it is particularly time-consuming to defrost so much ice that a drop in pressure becomes an indication.

The antifreeze device of the present invention eliminates the above drawbacks so that the heat exchanger is able to operate normally longer and at the same time make better use of the heat recovery plant, thereby achieving balanced and environmentally sound air conditioning. This is achieved by antifreeze protection according to the present invention.

*: ··· with a device whose structural features are claimed

: *. contracts. ? ··· ':. Figure 1 of the drawing is a cross-sectional view of a heat exchanger with an anti-freeze device according to the present invention, and Figure 2 is an enlarged cross-sectional view of a plate of heat exchanger cartridge containing water and j.

• · · 'V ;? * · * Condensation indicator.

Warm exhaust air is sucked into the heat exchanger by means of exhaust * 30 air blowers from 6 rooms or houses via the supply air channel v * * * ϊ.,. Ϊ 7, through the heat exchanger cartridge 1 and blown out,. through the exhaust air duct 8. The outdoor air or supply air is sucked in by · · # with the supply air fan 5 through the outdoor air duct 9,? • · '1 · "* through heat exchanger cartridge 1 and blown into the room ·, ·.' · 35 through supply air ducts 10.

····· • · 117647 '>. 3

The exhaust air ducts and the supply ducts are arranged alternately in the heat exchanger cassette 1 and separated by duct walls 11.

Preferably, the exhaust air duct is provided with a frozen-5 mi senes thermostat 3, which registers the exhaust air temperature, and a water and condensation detector 2, preferably arranged in the exhaust duct, to register any water present in the exhaust air. Further, the antifreeze thermostat 3 may be provided in the exhaust air duct or in the exhaust air duct of the heat exchanger cartridge 10 with the water detector 2. The antifreeze thermostat 3 may be provided in an exhaust duct or exhaust duct with a water detector 2.

The water / condensation detector 2 shown in Fig. 2 is attached to a heat exchanger cartridge outlet | an air duct and has aluminum strips 14 engaging the adjacent cassette walls, an electrical insulation 12 provided on the aluminum strips, and a second aluminum layer 15 arranged between the electrical insulation layers 12. The exhaust air flows along the edges of the layers 12, 14 and 15 on either side, and any water and condensate 1 «···· in the exhaust air descends to the edges of the layers, the outer aluminum layer 14 may be 0.5 mm aluminum and 9 volts, for example. can be adjusted in the outer aluminum layers 14 and in the middle ♦ · · '' **! 25 between the aluminum layer 15. In the middle of the aluminum • · · •. .

The "" nickel layer 15 may be 0.7 mm aluminum.

• · · · · ** ·· 1 As moisture settles to the edges of the layers as water | * · ·. -% • · · * · 1 The electrical insulation between the outer aluminum layer 14 and the inner aluminum layer 15 produces an electrical surface leakage:. · .Ϊ 30. Water and condensate settle on the upper surface of the layers 13 * · · ϊ.,. Ϊ and also on their lower surface. This surface leakage current can be noted that the outer aluminum layer 14 and the center 1 • 1 1

the voltage between the aluminum layer 15 is changed. I

• · • 1 1 *

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♦ »* 1 ·? • · ·. j • 1 * ··· * ·: 117647 4

Fig. 1 shows an electric control device 4 which controls the operation of the fan based on the information provided by the water / condensation detector 2 and also by the antifreeze thermostat 3.

In addition to the detectors shown in Fig. 1, the temperature detector 5 may indicate the temperature of the exhaust air. Even when the temperature of the exhaust air decreases, the supply air fan 5 will continue to operate if the water / condensation indicator 2 does not detect the presence of water. For this reason, there is no need to fear ice formation.

However, if the relative humidity of the indoor air rises due to spraying, washing and drying, etc., the supply air blower 5 will close. Such an increase in humidity is transient and occurs only for short periods during the day. This means that the heat recovery plant normally operates most of the time. |

If the water / condensation detector 2 detects the presence of water when the antifreeze thermostat 3 registers a temperature equal to or below a predetermined low temperature 20, the supply air blower 5 will stop and restart only after the water detector 2 no longer detects the presence of water.

; ·. If the heat exchanger cartridge 1 cools below the freezing point, the supply air fan 5 will continue to operate • 1 · 25 normally unless the water indicator 2 indicates the presence of water or condensate * 2 1 "2;

• 1 2 *! "'However, when using a shower or similar device, 1 * · 2 1 the moist air will condense as soon as it enters the heat exchanger cartridge 1. Water indicator 2 extending over the entire heat -:. ·, Ϊ 30 exchanger cartridge length , ensure that the supply air blower 5 has stopped and further ice formation is avoided.

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Claims (2)

5 1 1 7647 Antifreeze device for use in a transverse flow type heat exchanger wherein the exhaust air and the outside air pass through the plate passages of the heat exchanger cartridge and wherein the antifreeze device also comprises a supply air blower (5), an exhaust air blower (6) and antifreeze thermostat / condensation detector (2) is provided in the exhaust air duct of the heat exchanger cartridge 10, the electrical control device (4) ensures that the supply; the air blower (5) stops if the exhaust air temperature drops below a predetermined level, if the water / condensate indicator (2) simultaneously indicates that water or condensation is present, and that the antifreeze thermostat 15 (3) is arranged downstream of the exhaust air duct. 1 2. Antifreeze device used in a transverse-flow type heat exchanger in which the exhaust air and external air pass through plate ducts 20 of the heat exchanger cartridge and wherein the antifreeze device also comprises a supply air blower (5), an exhaust air blower (6) and a frost | • · antifreeze thermostat (3), characterized in that | • ♦ • * ·· The water / condensation indicator (2) is arranged in the heat exchanger: cartridge exhaust air duct, the electric control unit (4) at the rear ensures that the supply air fan (5) stops if the exhaust air * »·· . . *. the temperature drops below a predetermined level when - ···. ···. ·. * Water indicator (2) simultaneously indicates that water or condensate I is present and that the antifreeze thermostat (3) is provided in the exhaust air duct with the water indicator (2) • · ***** 30. J • »• * • * · * · * * · · ** · * * · * * * * * * '> * · ·.: ...- 5 • * · • · · j ··» · · • «117647 6