LT5729B - Method and device for energy-saving individual ventilations with multi-chain recuperation - Google Patents

Abstract

The invention relates to indoor ventilation technical field - personal venting methods and equipment, where by the outgoing air temperature recuperation method and equipment, incoming air is used to reduce the temperature difference, with regards toair temperature in the room. The aim is to make exhausting air temperature maximally close to the incoming into the room air temperature and out removed air temperature to the outdoor temperature. It is resolved by multi-chain recuperation with in respect opposite directions of the moving air flows. This method is realized in the new-energy-efficient individual ventilation device in which the thermal insulation, during ventilation, may be ensured in rate close to 100 % compared with a known techniques and equipments. There are also provided further improvements of the construction of device performance.

Description

Field of the Invention The invention relates to the field of indoor ventilation technology - individual ventilation being also for units where the outlet air temperature is utilized to reduce the difference of the incoming air temperature with the help of recuperation methods and devices in relation to the indoor air temperature. The task of maximizing the temperature of the supply air to the temperature of the exhaust air and the temperature of the exhaust air to the outside has been solved by a multistage recirculation circuit with air flows moving in opposite directions. This method is implemented in a new energy efficient individual ventilation unit, where the thermal insulation during ventilation can be ensured by an amount closer to 100% compared to known methods and devices. At the same time, design solutions that improve other device performance are provided.

BACKGROUND OF THE INVENTION Field of the Invention The invention relates to the field of indoor ventilation technology - ventilation methods and devices, whereby the outlet air temperature by means of recuperation and devices is used to reduce the difference of the incoming air temperature relative to the indoor air temperature.

In modern buildings, centralized ventilation systems with equipment for air heating, cooling, recirculation, recuperation and other types of air conditioning are widely used. However, such systems are expensive, complicated, and inadequate in terms of energy consumption, not only due to internal technical solutions, but also due to the need to install a ductwork for the building and the energy loss therein. Such devices have high maintenance costs because they are complex and require qualified maintenance. In the event of an accident or leak, the harmful vapors of freon and antifreeze used in such systems may enter and contaminate the ventilated area.

In order to avoid the drawbacks of centralized ventilation systems, individual ventilation equipment is constructed using the recuperation method known from centralized ventilation systems and corresponding units.

A known device is available. DE3426778 (A1), which can be installed in a window recess, frame or door structure. It has one recuperative heat exchanger in which the free-circulating outgoing and incoming air streams have a thermal contact through the heat-conducting surfaces of the recuperator unit. This allows their temperature to equalize and, according to the inventor, saves about 50% of the heat of the air removed to the outside, which is transferred to the air entering the room. Such a device is unstable and may not always meet the ventilation needs. This is because the free flow of air flows is dependent and influenced by many factors: wind direction and strength, difference in outdoor and indoor temperatures, building architecture, ventilation of other rooms, and the like.

On the device pat. No. DE100110817 (A1) has resolved the issue of maintaining ventilation volume. It takes air from outside, pushed by one fan, forcibly passes through its recuperator vents, and exits the room by pushing another fan, forcibly passes through other vents in the same recuperator, perpendicular to the intake air and enters the room. This way, the design already ensures stable operation, and the amount of ventilated air can be adjusted as needed - by changing the fan speed.

As with DE3426778 (A1) - DE100110817 (A1), only the supply air and extract air temperatures can be equalized in one recuperator. These are the indoor and outdoor air temperatures, approximately half the difference between indoor and outdoor air temperatures - the amount and heat capacity of the supplied and exhaust air are similar, there is no condensation process, and the heat dissipation caused by the fans the coefficient of performance is negligible.

It is an object of the present invention to provide a method and apparatus for individual ventilation whereby the temperature of the air supplied from the open air to the room is close to that of the indoor air while the temperature of the exhaust air is indoors. This goal should be achieved without the use of additional energy for heating or cooling of the air streams, with ventilation providing 100% thermal insulation as close as possible, thus saving the energy available to maintain the room temperature.

To achieve this goal, the technical challenge is to increase the depth of the recovery. This means transferring more energy from the cooling stream to the warming stream.

In a normally cross flow recuperator, which does not condense water vapor and does not release condensation energy, energy exchange processes are limited by the second law of thermodynamics. According to it, during the thermal contact between the heat-conducting walls of the recuperator ducts, the cooler stream warming cannot reach a higher temperature than the drop in the cooler cooler stream temperature. In this case, the relation of the output flow temperature change is determined by the energy holding law, according to which the heat energy delivered by the warmer flow is equal to the thermal energy obtained by the cooler flow. With uniform flow rates and similar thermal capacitance characteristics, the temperatures leaving the recuperator streams can almost equalize to values close to the average of the inlet temperatures. Such an effect is observed empirically and was stated by the author of DE3426778 (A1), according to which his device saves approximately 50% of the thermal energy (which would be lost by the ventilation of the room without heat exchange).

In the present invention, the problem of the depth of recovery is solved by splitting the process of recovery into a circuit of separate recovery steps, in which the flows of supply air and supply air flow sequentially throughout the circuit, but in opposite directions.

Due to the difference in outdoor and indoor temperatures, heat exchangers between the circuits in heat exchangers in such a circuit, and therefore the temperature of the flows, change. In this way, each of the recuperators in the circuit produces different ranges of inlet temperatures that are occupied but of similar size, each individually below the range of outdoor and ambient temperatures and generally covering it completely. The smaller these ranges, the greater the number of recovery steps. Thus, the inlet temperature differences between each of the recovery stages are reduced, completely covering the entire range defined by the difference between outdoor and indoor temperatures.

The temperature of the output streams from each recuperator is determined by the energy holding and the second laws of thermodynamics. The volumes and heat capacities of the supply air and exhaust air in the closed room ventilation are similar, therefore, according to the law of energy endurance, their temperature in the recuperator changes by a similar amount, to the opposite of the two temperatures. According to the second law of thermodynamics, the output flows from a single recuperator temperature cannot pass, but only come closer and, ideally, unify. One-way flow heating is involved in recuperators forming the lower part of the temperature inputs, while the other direction flow is driving the upper part of the temperature inputs. The outputs of the recuperators are transmitted in different directions towards the outlet of the ventilation unit corresponding to their temperature change.

With many such tiers, the closest tier to the room has a relatively small difference in the inlets: the exhaust air removed - the air coming from the outside through the other tiers. Therefore, even after its exit, the temperature difference between the supply air and the room air will be relatively smaller than without the previous steps. A similar effect will occur with the nearest step to the field.

The same principle and structure will act as thermal insulation where the indoor air temperature is higher than the outdoor air temperature and vice versa the indoor air temperature will be lower than the outdoor air temperature. The temperature distribution of the recovery steps will then automatically reverse in the opposite direction and save energy for cooling the room.

Water vapor condensation in the cooling exhaust air stream (when the room temperature is higher than outside) can only improve the energy saving effect at the expense of condensation energy. The water vapor condensation energy released in the form of heat is involved in further heat exchange in the subsequent recovery steps according to the direction of flow motion. Using multiple steps allows you to make better use of this energy.

In recent recuperators, the problem of recuperative depth is solved in another way by significantly altering the longitudinal and transverse thermal conductivity properties of recuperator plates by changing geometric shapes. Manufacturers of recuperators with "V" shaped cross-corrugated plates declare improved performance of their products.

Two-stage recuperators are found in centralized ventilation systems, but multistage decomposition, unlike individual ventilation systems, was not relevant here and was not applied due to the high energy consumption of other functional circuits. Two recovery steps improve the desired quality of the recovery process by no more than 1 / 6th of a degree compared to one step.

In addition to the main object of the invention, known and freely applicable methods, the following additional problems have been solved: 1) reduction of the fans by decomposing them; 2) noise reduction of fans and utilization of thermal energy emitted by them by placing them inside the recirculation circuit; 3) resulting fluid leakage - by positioning the components connected by ducts vertically and providing for escape holes; 4) possible ice melting - by providing for heating by electric or thermal contact with warmer medium; (5) manual or automatic control of the amount of ventilation by installing dampers for full stop and by regulating the speed of rotation of the fans within the operating range of the fans; (6) anti-fouling measures, including elements for retention and accumulation of contaminants (eg grilles, filters, accumulation pits); 7) additional thermal insulation - forming the thickness of the shell walls or additional layers of thermal insulation; 8) ease of service - providing for simplified removal, disassembly, and use of remaining openings alternatives.

The method of ventilation, and the device, in solving the exact object of the invention in a multi-stage recuperation variant, have the following features:

1. General, freely usable.

1.1. The ventilation of the room and the associated air treatment are carried out in an individual ventilation unit.

1.2. Heat exchange between the supply and exhaust air streams is done through a recuperation process.

1.3. The required ventilation flows are provided by the fans.

2. Exceptional.

2.1. The recuperation process is divided into a temperature-coherent, long (not less than three-element) recuperation step circuit, so that the supply and exhaust air streams pass the entire recuperation step circuit in a sequential but opposite direction.

2.2. In the case of 2.1. a distinctive feature is that the flow fans for each flow can be split into several fans that run consistently over the flow.

2.3. In the case of 2.1. a distinctive feature is that fans can be housed inside a recirculation stage, or have other noise reduction means.

2.4. In the case of 2.1. for exceptional features, the fan speeds may be manually or automatically controlled and the air inlets and outlets may have manually or automatically closed valves.

2.5. In the case of 2.1. For distinctive feature, the units of the ventilation units can be vertically arranged and the ducts of the ventilation ducts can be slanted, smooth and have openings for the discharge of the resulting liquid.

2.6. In the case of 2.1. for distinctive features, air inlet and outlet openings and ducts may include elements for containment and accumulation.

2.7. In the case of 2.1. as an exceptional feature, the lower part of the exhaust air duct can be additionally heated by manual or automatic control.

2.8. In the case of 2.1. As an exceptional feature, unwanted heat circulation is suppressed by the use of a heat insulating body, additional layers of thermal insulation, or a combination thereof.

2.9. In the case of 2.1. as a distinctive feature, the housing may include accessories for simplified multiple disassembly, insertion, removal, and use of the remaining openings as a simple vent without destroying or weakening the structure in which it is embedded.

This method and the apparatus operating therein are further described by examining the functional sectional diagram of the apparatus comprising fifteen recovery steps shown in the drawing. It consists of: heat insulating housing - 1 with exhaust air 2 and supply air 3; fifteen small recuperators installed in the housing - 4; two electric, axial, low power exhaust fans - 5; three electric, centrifugal low power air supply fans - 6; lower heat-conducting exhaust duct plates - 7; heat insulating frozen condensate outlet removable plug - 8. The housing 1 wall between the outside portions of the inlet and outlet duct has a recess-9 for accumulating heavier particles taken from the outside air and a small diameter hole in the center to drain water into the bottom of the exhaust air duct . Exhaust and supply air flow lines with directional arrows are shown in the center of the duct. The recuperators and fans are represented by typical flowchart designations.

The recuperators 4 are arranged in a casing 1 in a series of vertical circuits. Their vertical exhaust air ducts are connected by a duct 2, in which fans 5 are inserted between the recuperators. The upper opening of the duct 2 is intended for the intake of air from the room. The lower opening of the duct 2 is intended for exhaust air. Fans located between recuperators 4 in duct 2 5. Ducts of horizontal recuperators 4 are connected by ducts 3. Fans 6 are embedded next to recuperators 4 in duct 3 6. The bottom duct 3 is raised above and has an opening for the intake of outdoor air. Duct 3 is lowered from above and has an opening for air supply to the room. Above the lower part of the duct 2, the duct 9 is formed in the duct 3 and has a hole 10 at its lowest point for the removal of water that has entered the outside air. The lower part of the duct 2 is formed as a separate plate 7 which is covered by a pin 8 of a heat insulating material.

As the fans 5 and 6 rotate to provide the necessary ventilation flows in opposite directions to the vertical, the exhaust air from the room through the duct 2 successively passes the recuperators 4 corresponding to the recovery stages and gradually changes its temperature in each. At the same time, in the opposite order, the recuperators 4 corresponding to the recovery steps, only through their other ducts, pass the air from the outside and gradually change their temperature in each.

The composition and operation of the device described herein implement a method that solves the main object of the invention. The currents move in opposite directions through a chain of recovery steps, where the heat exchange is divided into steps. Significantly less variations are made for each recuperator than for outdoor and indoor temperatures - the inlet temperatures that each recuperator shifts relative to one another. The output temperatures determined by the heat exchange take intermediate values from the range of input temperatures, separate for each step. These intermediate values for both inlet and outlet flow temperatures are much closer to atiLT 5729 B for proper indoor and outdoor air temperatures than would be the case for a single recuperation step of similar quality.

The process system described can be realized by producing axial and centrifugal fans, as well as rectangular or other plate or tubular recuperators, by placing them in a heat insulating (for example, porous plastic) casing with ducts and component locations.

Claims (10)

DEFINITION OF INVENTION 1. Energy-efficient individual ventilation with multi-stage recuperation, where: single room supply and exhaust air streams are pushed by separate fans, the two streams are converged but not mixed, the recuperator, each flow is routed by non-contact air ducts and all elements a casing in which exhaust air is supplied and discharged through separate openings; characterized in that each of the two streams passes through a chain of multiple (at least three) recuperators sequentially but in the opposite order. 2. Energy-saving individual ventilation unit with multi-stage recuperation consisting of a housing containing a single room air treatment unit with separate supply and exhaust air inlet and outlet openings and internal non-contacting supply and exhaust air ducts with separate fans and connected to separate recuperator , which ensures thermal contact of the air streams without mixing them, with channels characterized by a plurality of (at least three) recuperators in the supply and exhaust air channels arranged so that the supply and exhaust air channels connect the same recuperators in a consistent but opposite order of flow. in terms of flow directions. 3. The apparatus of claim 2, wherein the flow rate fans are distributed over several flow-rate fans. 4. A device according to claim 2, characterized in that the fans are located inside the recirculation stage circuit or have other noise reduction means. 5. A device according to claim 2, characterized in that the fans have an automatic or manually controlled rotary speed regulator and the air inlets and outlets have automatic or manually closed and open flaps. 6. A device according to claim 2, characterized in that the ventilation units are arranged vertically and the ducts of the ventilation ducts are sleek and have self-discharge openings for the resulting liquid. 7. A device according to claim 2, characterized in that the air inlet and outlet openings and the ducts contain elements for the containment and accumulation of pollutants. 8. A device according to claim 2, characterized in that the lower part of the exhaust air duct comprises structural components for manual or automatic defrosting of the ice formed. 9. A device according to claim 2, characterized in that the housing has means for thermal insulation. 10. A device according to claim 2, characterized in that the housing contains additional components for simplified reusable removal and insertion, and for use of the remainder of the opening after removal as conventional vents without destroying or weakening the structure in which the device is incorporated.