AIR RECOVERY SYSTEM IN A HOUSE OR APARTMENT

What is a recuperator?

The air recuperation system allows to significantly decrease the air heating cost. During a room ventilation process, the warm air (that was previously heated using energy and financial means) may be lost. Using a recuperator allows to retain and reuse this heat without wasting money. 

So, what exactly recuperator is?

A recuperator is a heat exchange device that transfers heat from the exhaust air to the cold supply air. This device helps an already heated air to enter the house or. As a result, there is no need to spend additional energy on heating the air in the rooms.

Recuperated ventilation in a private house or apartment begins with the selection of a suitable device. Here is a list of factors that must be taken into consideration when designing a ventilation system with a recuperator:

• Size of living space area
• The number of residents

Each recuperator has its efficiency. This indicator is affected by the temperature of the intake air and the level of humidity. The warmer the intake air and the higher the humidity, the more efficient the recuperator is. Therefore, the intake of humid exhaust air from “dirty areas” by means of ventilation units increases the efficiency of the recuperator.

How does the recuperator work?

Such devices are gaining more and more popularity among clients. An easy operation fully demonstrates the practicability of purchasing supply and exhaust ventilation equipment with a recuperator for a house and an apartment

Important!

The higher the temperature of the exhaust air, the more it will be possible to heat the supply air.

Installation of a ventilation system with a recuperator reduces possible heat loss without compromising the quality of air exchange

​Types of recuperators in ventilation systems 

The recuperators used in ventilation systems in details: they differ in performance characteristics.

There are two types of ventilation installation:

• vertical - placed in technical rooms or integrated into furniture;
• horizontal - installed under the ceiling.

Vertical ventilation units with recuperation are mostly installed for domestic use (apartments and houses up to 250 m2) since they are more energy-efficient due to the large surface area of ​​the recuperator.

• In order to save resources, for a long time, many countries in Europe and other parts of the world have been using recuperation in ventilation systems for heating homes. 
• Most often, the following types of heat exchangers are used in ventilation equipment:
• Rotary recuperator is a special disc-like heat exchanger, which is filled with corrugated metal sheets closely spaced to each other. The device has an electric motor that drives the recuperator. As they rotate, the heat from the intake air heats these plates. And when the disc enters the supply air zone, the stored heat in the plates is transferred to it, thereby heating it. Rotary heat exchangers are reliable and efficient.
• The plate recuperator is designed to divide an airflow by metal plates. It does not have any moving parts, unlike rotary ones. Plate heat exchangers are popular because they are easy to manufacture and have a compact design. When the outside temperature is low, there is a possibility of freezing of the device, therefore condensate drainage is necessary. Plate recuperators can be polypropylene, plastic, metal, and enthalpy.
• Enthalpy recuperators - in addition to heat, such recuperators also transfer moisture to the supply air, which eliminates the necessity of drainage. The disadvantage of the enthalpy recuperator is its short duration of use. It is recommended to install it only during the winter period.
• Filtration. To ensure the smooth operation of the recuperator, it is important to have air filtration. To avoid contamination of recuperator, a G4 class filter is installed for taking exhaust air is in “dirty zones” - kitchen, bathroom, dressing room. 

Since condensation forms on most recuperators, the ingress of dust on its surface can lead to the formation of fungus.

The enthalpy recuperator does not have condensation, but its porous surface can also become contaminated with micro-dust, which adversely affects the efficiency of its operation. Therefore, when using an enthalpy recuperator, it is necessary to strictly control the regular replacement of filters.

Post- and preheating. The temperature is controlled by a pre-heater and a post-heater in low-cost brands with ineffective recuperation. This protects the recuperators from freezing.

For example, in Jablotron ventilation units, the power of the heating element for post-heating is only 300W. In other systems, the heating element is more powerful, which indicates a lower quality of the recuperator.

This topic is discussed in the article "Comparison of Maico WS and Jablotron Futura installations" in further details. It is recommended for reading

DECENTRALIZED VENTILATION SYSTEM

A decentralized air recuperation ventilation system has a local air supply in a separate room. Such systems are easy to install (they can be installed into the wall easily even after the apartment renovation is complete), do not require dilution of air ducts and additional equipment.

However, compared to a centralized system, decentralized ventilation with a heat recuperator is less efficient.

To implement such a system, the equipment from the following manufacturers is the most suitable:

• ​Meltem, 
• ​Zehnder, 
• ​Maico, 
• ​Mitsubishi Electric, 
• ​Soler&Palau. 

As an example, let’s examine ventilation with a Maico PushPull household recuperator. Most often, they are used in combination with exhaust fans (usually in the kitchen and bathroom). As a standard, these devices work in pairs (two units are located in adjacent rooms): one of them is for air supply, and the second is for discharge, after a certain time they change functionality. When the exhaust fan starts working in the bathroom or the kitchen, the air handling units begin to work on the inflow, compensating for the reclaimed air volume. Air movement around the apartment is implemented by a non-road system.

A decentralized air recuperation system has several disadvantages:

1. Low efficiency due to the lack of air distribution in the room
2. At a low temperature, the device may freeze, since it was originally manufactured for countries with a southern climate
3. Small amount of supplied air 

The cost of ventilation with a household recuperator depends on the equipment. An example described above with Maico PushPull will cost around 27000 UAH per room.

Air handling ventilation unit Meltem also deserves attention. It can be used not only as a decentralized ventilation system since a system of air ducts can be installed with it, making it a centralized ventilation system. With the help of air ducts, air will circulate through the room and be distributed through air diffusers. This will make the system perfect for small spaces and more efficient.

The estimated cost of centralized ventilation based on Meltem is 100,000 UAH.

Watch our video for more information about the Meltem ventilation unit:

CENTRALIZED VENTILATION SYSTEM WITH RECUPERATION

The centralized ventilation system implies the installation of the ventilation unit with the distribution of air ducts to different rooms. Such a system provides a full-fledged high-quality air exchange: clean air is supplied to living rooms, the so-called "clean zones" - bedrooms, living rooms, children's rooms. At the same time, exhaust air is taken from the “dirty zones” - kitchens, bathrooms, dressing rooms.

Air distribution in the room is performed through diffusers or vents.

In our office, hidden linear diffusers are installed. A demonstration of their work can be viewed in the video.

To arrange a centralized ventilation system, equipment from Jablotron, Meltem, Systemair, Zehnder, Salda, Maico can be used.

The design of the recuperator in the Jablotron ventilation unit deserves special attention.

First of all, it allows to keep warmth and moisture inside of a room. Also, the heat exchanger is equipped with 4 moving dampers that change the direction of the airflow. This technology makes the Jablotron air recuperation system highly efficient and protected from freezing.

Moreover, the “air-to-air” heat pump Jablotron CoolBreeze module can be used as an additional function for temperature control. This is an excellent solution for air cooling during the demi-season and at night. However, CoolBreeze cannot replace a full-fledged air conditioning system in the hot season.

To get more information on this topic, we advise reading our article where we analyze the efficiency of the Jablotron and Maico ventilation units in details.

THE COMPARISON OF OPERATION OF THE MAICO WS AND JABLOTRON FUTURA UNITS,​

The approximate cost of implementing a centralized ventilation system based on Jablotron is 300,000-350,000UAH.

CENTRALIZED VENTILATION SYSTEM WITH JABLOTRON RECUPERATION WITH CO2 SENSORS AND VAV SYSTEM FOR VARIABLE AIR SUPPLY

When it comes to ventilation with recuperation, it is important to pay attention to the automation of the system. Most manufacturers of ventilation systems consider automation as an additional option and are sold separately.

The Jablotron ventilation system has the most convenient automation.

Moreover, Jablotron provides additional functionality - air quality control using CO2 sensors, as well as a VAV system for variable air supply.

How does this work?

CO2 sensors monitor the air quality in rooms. As soon as the sensors record an increase in the amount of carbon dioxide (in case there are people in the room), the system signals the VAV valves to open and forcefully supply clean air to the area. In the rest of the premises, with no people, the system works only to maintain the norm for the indicators. It is important to note that the installation tries to work as efficiently as possible at minimum speed, which ensures smaller energy consumption.

The system ensures that the air will not be “wasted” if people there are no people in the room, and the user does not need to manually control the operation of the ventilation unit. The system controls itself.

The installation of a centralized ventilation system Jablotron, equipped with VAV valves and CO2 sensors, costs about 400,000-450,000 UAH.

When installing a Jablotron ventilation system equipped with VAV valves, it is recommended to install a Faber kitchen hood. This combination has several significant advantages:

• Balance of supply and extract air during operation of the hood. Often, even if a ventilation system is installed, when the kitchen hood is operating, the amount of extract air in is greater than the amount of supplied air. However, when Faber kitchen hood is installed with Jablotron ventilation system as a set such issue does not arise. Jablotron ventilation and Faber kitchen hood are united by common automation. When the hood is activated, the system intensively extracts air from the kitchen in order to prevent the spread of odors throughout the house. At the same time, in the rest of the "dirty areas"(a bathroom, a bathroom, a wardrobe), the VAV valves are automatically closed. If the volume of the intake air exceeds the amount of the supplied air, the unit increases the capacity to compensate the extracted air with the supply air. Thus, there is always a balance and high-quality air exchange in the house, even during intensive cooking.​

• Accumulation of heat coming from the frying surface. The Faber kitchen hood is connected to a ventilation system, so it does not discharge warm exhaust air on the street through a separate ventilation duct. Recuperator helps the system to retain and reuse the heat of the intake air, also, it transfers heat to the air and supplies already heated air. The Faber hood is equipped with a filtration system that protects the recuperator from various contaminants. Thus, in addition to the energy efficiency of the Jablotron VAV unit itself, the variable air supply VAV system provides the user with the additional benefit of storing and reusing heat from the frying surface. This reduces the load on the heating system in winter.С