RU2797625C1 - Ventilation unit with heat recovery - Google Patents

Abstract

FIELD: climate control in premises.

SUBSTANCE: device can be used to organize air exchange and ensure moisture and heat balance in premises with significant moisture and heat emissions. The unit is placed indoors and comprises an inlet and outlet chambers, an adjustable inlet louvre, parallel pipes fixed in tube sheets, one or more fans installed in the outlet chamber, adjustable louvres located in the inlet and outlet chambers from the side of the premise. The pipes are placed in a box and placed in such a way that between each four adjacent pipes of a larger diameter, pipes of a smaller diameter are equidistant with a gap and parallel to them. The bottom of the box is a tray equipped with a condensate drainage system. The box on the side of the outlet chamber is provided with an inlet channel connected to the fan, and on the reverse side with two outlet channels, one of them is equipped with a control valve and is connected to the exhaust ventilation system of the premise.

EFFECT: improved efficiency of the unit.

1 cl, 2 dwg

Description

The invention relates to ventilation and can be used to organize air exchange and ensure moisture and heat balance in rooms with significant moisture and heat emissions, in particular livestock buildings.

A well-known ventilation system for premises (patent RF 2076282 F24F 7/00), including supply and exhaust fans, supply duct with an intake opening, supply air duct with laminar ejection air distributors, exhaust air duct, utilization heat exchanger, made in the form of parallel pipes fixed in tube sheets, and tray placed under the heat exchanger.

This system makes it possible during cold periods of the year to heat the supply air in the utilization cross-flow heat exchanger using the heat of the recirculated (sent to the air curtain) air. When internal moist and warm air passes through the heat exchanger tubes and blows them from the outside with cold supply air, condensate is formed with the release of latent heat of condensation, thereby ensuring air drying with the effect of maintaining the heat balance in the room.

The disadvantage of the ventilation system is the possible formation of frost and ice on the inner surface of the heat exchanger pipes, which leads to a decrease in the efficiency of heat exchange between the supply and recirculated air and even to clogging of the pipes. The cross flow of heat carriers is less efficient than the counter flow. The ventilation system is structurally complex, since the prevention of blowing cold jets is achieved by mixing the supply air with warm internal air in special ejection devices.

The closest in terms of set of features to the proposed technical solution is a supply and recirculation unit (RF patent 2643420 F24F 7/00), including parallel pipes fixed in tube sheets, a tray placed under them with a condensate removal system, a receiving chamber with an adjustable supply louvre, an outlet a chamber with fans, both chambers on the side of the room are equipped with adjustable louvered grilles, and holes are made in the tube grilles, and in the intake chamber grille they are made with the possibility of adjusting the flow area.

This air handling unit performs air drying with the release of heat of phase transformation, controlled forced supply of supply and mixed internal air and their mixing in different proportions depending on the season with controlled air exchange from minimum in the cold period to maximum in the warm period, which eliminates icing of the tube bundle of the heat exchanger and blowing with cold jets of air introduced into the room.

The disadvantage of the prototype is insufficient mass transfer to condense water vapor from the air due to low heat and mass transfer coefficients outside the pipes due to the low speed of the air washing these pipes in the room. The prototype does not provide for an exhaust ventilation system combined with the device in question, so the heat of the exhaust air from the room is not used to heat the supply air. These shortcomings explain the low efficiency of the prototype.

The technical task of the claimed invention is to improve the efficiency of the installation.

This problem is solved due to the fact that the claimed ventilation unit with heat recovery, located in the room and containing parallel pipes fixed in tube sheets, a tray with a condensate removal system placed under them, an intake chamber with an adjustable supply louvre, an exhaust chamber with fans, and both chambers from the side of the room are equipped with adjustable louvered gratings, the pipes are placed in a box, the bottom of which is aligned with the pallet, between each four adjacent pipes, equidistantly with a gap and parallel to it, pipes of a smaller diameter are fixed in the tube grates, and the box on the side of the outlet chamber is equipped with an inlet channel, attached to the fan, and on the reverse side - two output channels, one of them is equipped with a control valve and is connected to the exhaust ventilation system of the room.

In FIG. 1 shows a longitudinal section of a ventilation unit with heat recovery, FIG. 2 - cross section.

The installation is located in room 1 and contains an adjustable supply louvre 2, a receiving chamber 3 with adjustable louvres 4, a single-pass heat exchanger made in the form of pipes 7 and 8 fixed in tube sheets 5 and 6, installed with a gap 8 relative to each other, an outlet chamber 9 with adjustable louvres 10, one or more fans 11 installed in the outlet chamber 9. The pipes are placed in a box 12, provided on the side of the outlet chamber 9 with an inlet channel 13 with a fan 14, and on the side of the receiving chamber with a recirculation channel 15 and an outlet channel 16 with a control valve 17. The outlet channel 16 is connected to the exhaust ventilation system of the room, and the tray 18 of the box is equipped with a condensate removal system 19. The recirculation channel 15 can be connected to the air curtain of the gate. Preferably, the pipes and duct can be made of a polymeric material to prevent corrosion.

The installation works as follows.

During the operation of fans 11, due to the vacuum created by them through an adjustable louvre 2, the supply air enters the receiving chamber 3 and moves through pipes 7 and 8. In the cold periods of the year, these pipes through the channel 13 are blown from the outside with a counterflow by means of a fan 14 with warm and humid air from the premises. As a result of heat exchange, the cold supply air is heated, part of the cooled air blown from the room is sent to the channel 16 regulated by the damper 17 for exhaust from the room, and the other part through the channel 15 returns back to the room, for example, to the air curtain of the gate of the livestock building. The contact of warm and humid air moving in the annular space with cold pipes 7 and 8 leads to its cooling below the dew point and condensation on the surface of the pipes with the release of latent heat of vaporization. This heat is perceived by the supply air, which helps to maintain the heat balance of room 1. The recirculated air returned to the room through channel 15 is cooled, but dehumidified, which helps to reduce the required air exchange in the room with significant moisture emissions. Placement between pipes 7 of large diameter pipes 8 of smaller diameter allows you to increase the heat and mass transfer surface of the ventilation unit by about 25-30%, the air velocity in the annular space and thereby intensify heat and mass transfer and reduce the dimensions of the unit. The heated supply air enters from pipes 7 and 8 into the outlet chamber 9, where, due to the vacuum present in this chamber, room air is mixed in through adjustable louvres 10. As a result, the temperature of the air blown into the room 1 by the fans 11 is close to the air temperature in the room. The placement of several fans 11 in the outlet chamber 9 contributes to the achievement of a more uniform vacuum pressure throughout its entire volume. The condensate formed on the surface of the tube bundle 7 and 8 is collected in the sump 18 and discharged through the system 19, for example, into the sewer.

When the outside air temperature is below minus 10-15°C, to prevent icing on the surface of pipes 7 and 8 and reduce air exchange, the louvered grilles 4 are slightly opened. This leads to a decrease in the intake of fresh air and mixing warm air from room 1 into it. further reduce the intake of fresh air by covering the louvre 2.

When the outside air temperature is above minus 5°C, adjustable louvered grilles 4 and 10 are covered, which leads to an increase in air exchange, a decrease in the temperature of the air passing through pipes 7 and 8, which contributes to condensation on the outer surface of these pipes and drying the air inside room 1.

During the warm period, adjustable louvres 4 and 10 are completely closed, and the fan 14 is turned off. The device operates with the maximum supply of supply air without recirculating the internal air and drying it.

The performance of the exhaust ventilation system of the room must correspond to the performance of the supply ventilation. In the event of excessive closing of the damper 17 or when the fan 14 is turned off, the air can be extracted from the room through additionally mounted exhaust shafts or ducts.

Thus, the ventilation unit with heat recovery ensures efficient operation due to heat exchange between the supply and exhaust air, drying of the recirculated air with the release of heat of phase transformation, forced supply of supply and recirculated air, adjustable mixing in different proportions depending on the season to the supply air of the internal air , controlled air exchange from the minimum in the cold period to the maximum in the warm period, the exclusion of icing of the heat exchanger pipes and the blowing of cold jets of air introduced into the room.

Claims (1)

Ventilation unit with heat recovery, placed indoors and containing parallel pipes fixed in tube grids, a tray with a condensate removal system placed under them, an intake chamber with an adjustable supply louvre, an exhaust chamber with fans, both chambers from the side of the room are equipped with adjustable louvres , characterized in that the pipes are placed in a box, the bottom of which is aligned with the pallet, between each four adjacent pipes equidistantly with a gap and parallel to it, they are fixed in tube sheets of pipes of a smaller diameter, and the box on the side of the outlet chamber is equipped with an inlet channel connected to the fan, and on the reverse side - two outlet channels, one of them is equipped with a control valve and is connected to the exhaust ventilation system of the room.

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