Buildings Special Issue on "Research on the Airtightness of Buildings" open for submission

A special issue of Buildings (ISSN 2075-5309)  is now open for submission.

This Special Issue is motivated by the importance of the airtightness of buildings in terms of indoor air quality and the energy implications of heat transfer. Currently, it is not possible to design and construct nZEB buildings without taking this parameter into account, and it is essential that we can determine this parameter in buildings to be renovated in order to achieve a significant improvement in their final energy consumption. 


Case Study: Heat Recovery and Demand Controlled Ventilation in Industrial Kitchens

Industrial kitchens have high HVAC load requirements due to high exhaust rates from hoods. Especially in cold climates to heat the makeup air in winter requires high initial and - more importantly - high operating costs. Heat recovery always looks like an attractive alternative due to the high temperatures of hood exhaust air. However, since hood exhaust is quite dirty, heat recovery sections are clogged very fast. Heat recovery systems are established in six restaurants in Ankara, Turkey.

Smart ventilation toward an assessment of airflow imbalance and supply temperature set-points

Many countries have mandated the use of mechanical ventilation with heat recovery to limit heat loss in residential buildings. Nearly all these devices use temperature sensors to modulate bypass dampers and adjust heat recovery. These controls track a reference temperature for the supply or return air while maintaining exhaust temperatures above freezing. As a result, nearly all air-handling units (AHUs) come equipped with temperature sensors before and after the heat exchanger for both airflows.

Quantification of the Impact of Indoor Temperature Gradients in Dwellings on Useful Recovered Heat of Ventilation Systems

Ventilation in buildings dilutes the indoor air pollutants by replacing part of the air with outdoor air to guarantee an adequate indoor air quality (IAQ). In heating-dominated climates, the exchanged air has a lower mean temperature than the indoor air, which leads to a surplus heating demand in the building. A heat exchanger recovers part of the heat from the expelled air, contributing to the reduction of the extra heating demand. Smart ventilation systems work with reduced airflows, without compromising the IAQ and lowering the heating demand.

Energy aspects and ventilation of food retail buildings

Worldwide the food system is responsible for 33% of greenhouse gas emissions. It is estimated that by 2050, the total food production should be 70% more than current food production levels. In the UK, food chain is responsible for around 18% of final energy use and 20% of GHG emissions. Estimates indicate that energy savings of the order of 50% are achievable in food chains by appropriate technology changes in food production, processing, packaging, transportation, and consumption.

Numerical optimization and experimental testing of a new low pressure heat exchanger (LoPHEx) for passive ventilation of buildings

Reducing primary energy consumption is an essential issue for the sector of building construction. This paper refers to building ventilation systems and focuses on low pressure flat plate heat exchangers, designed for low pressure drops and low air velocity, minimizing the electrical consumption of fans. The device is conceived for working within passive ventilation systems, as a ventilation heat recovery stage during winter and sensible heat dissipation during summer.

Alternative ducting options for balanced mechanical ventilation systems in multifamily housing

Duct routing often poses a great challenge when planning the installation of a mechanical ventilation system with heat recovery. This is particularly true for retrofits, where the necessary space for supply and exhaust ducts was originally not accounted for. This extended summary presents an alternative approach for duct routing avoiding ducts in the dwelling, while allowing the installation of a centralized MVHR unit and the implementation of a cascading airflow through the dwelling.

Multi-objective design of single room ventilation units with heat and water recovery

The present paper describes the design improvement of a single-room ventilation unit. This ventilation system presents many advantages, however, several drawbacks exist. The first one is the acoustic disturbance. As the facilities are directly installed within the rooms, the fans’ noise may create discomfort. Furthermore, in the cold or temperate climates, condensation or frost may appear. A dedicated management should then be implemented. Finally, as the system is not centralized, communication between the different units is required to ensure the global system efficiency.

A holistic evaluation method for decentralized ventilation systems

The implementation of decentralised ventilation units is growing, especially in the residential retrofit. These systems are typically simple to install on site (usually in the external façade with no additional ductwork) and allow room-by-room control strategies. Until now, decentralised systems are evaluated by applying the same methodologies as for centralised ventilation systems, even though different boundary conditions apply. Some differences are for example:  

Temperature, draft and ventilation efficiency of room based decentralised heat recovery ventilation systems

Mechanical ventilation systems with heat recovery are considered the most optimal systems for residential ventilation. This research focuses on decentralized ventilation which do not need any ducting. Therefore, this system is very suitable for use in retrofitting. The performance criteria of these units are similar to those of central systems. A recuperative and two regenerative ventilation units were tested in a double climate chamber where temperature, air velocity and contaminant concentration were monitored on a fixed 80 point grid.