As outlined in our previous blog, heat recovery refers to the process through which heat is extracted from the air - either inside or outside a building - and is reused to provide internal warmth. These ventilators, which form an auxiliary component within heating systems, allow property owners to obtain the greatest comfort for the lowest possible cost. Given that they don’t replace the need for primary heaters, however, many are prone to inquire why these are necessary.

Heat recovery - heat exchanger

Diving into why heat recovery is a crucial part of any building, the different systems available, and how these can be used for greater ventilation, continue reading our post to find out all you need to know!

Why is heat recovery essential in buildings?

Given that many buildings are created for human habitation, proper ventilation and good air quality are important for long-term health and comfort.

In maintaining these, Heat Recovery Ventilators (HRV) often play a decisive role. Without these systems, occupants are likely to suffer from a range of health conditions, even those as serious as asthma and allergies. These could be the result of a build-up of mould, dust, and pollens or due to the pollution brought in through cracks and other openings in a building.

Poorly ventilated buildings can also allow carbon dioxide to build up.

Beyond discomfort, this kind of situation can prove extremely dangerous for those who live or work in such properties. Among the many ill-effects that could be suffered, therein, sleepiness, lethargy, asthma, headaches, and a sluggish mental state are some of the most common side-effects.

With HRVs, however, these problems can be circumvented with relative ease. In this way, not only can property owners enjoy greater energy efficiency and lower costs, but also guarantee comfort and better health for internal occupants.

How can heat recovery take place in a building?

When it comes to ensuring proper ventilation in buildings, there are two primary ways in which heat exchange can take place. In this regard, heat recovery can be facilitated either through air or water - both of which will be discussed below.

Air-based systems

Air heat recovery systems are most often used to preheat or cool ventilation in order to reduce heat and cool loads in a building. While variants of this system employ different tools and methods to facilitate ventilation in a building, they all achieve the same purpose.

In particular, these solutions are useful when it comes to dealing with mechanical codes that don’t permit heat recovery. Here, run-around coils and heat pipes can be used to recover heat from contaminated airstreams, simply because both systems maintain separate airstreams without leaving any room for cross-contamination.

While this may depend on the type of air heat recovery system employed - run-around coil-based solutions, for instance - this is, nonetheless, a specific advantage that can be enjoyed through air-based heat recovery/ventilation systems.

Hydronic heat recovery systems

With these types of systems, the heat from the cooling process is reused for heating.

Based on the specific requirements of each building, specifically their heat loads, these systems can use the recovered heat to preheat a low-temperature heating hot water loop or a service hot-water loop to achieve this purpose.

In this way, not only is energy saved in the process of heating, but the energy used by various cooling tower fans and condenser pumps are also reduced. It is from these components that heat is expelled in the first place.

What should I know before I install a heat recovery system?

Before you install any type of heat exchange ventilator in your building, there are a few pointers that are worth keeping in mind. First and foremost, check your building codes and other related regulations. This way, you save yourself from liabilities attached to violations of these policies, specifically because contaminated air can be a serious issue.

Another best practice is to use energy models to determine the most efficient heat recovery strategy. In this way, you ensure that your ventilator system fits in with the primary heating and cooling solutions used in your building. It’s also useful to note that zone variable refrigerant flow solutions take maximum advantage of heat recovery.

Key takeaways

Heat exchange or heat recovery systems are becoming an increasingly important part of modern buildings. Given their ability to maintain the quality of internal air - ensuring, in turn, that occupants are healthy and comfortable - these systems need little more in terms of justification. Nonetheless, they also make their mark in ensuring supreme energy efficiency.

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Tags: Heat recovery, Heat exchanger