This study presents some results from a monitoring project with night ventilation and earthto- air heat exchanger. Both techniques refer to air-based low-energy cooling. As these technologies are limited to specific boundary conditions (e.g. moderate summer climate, low temperatures during night, or low ground temperatures, respectively), water-based low energy cooling may be preferred in many projects. A comparison of the night-ventilated building with a ground-cooled building shows major differences in both concepts.

This paper focuses on ventilation solutions of a net zero energy building. We present the monitoring results after two years as part of the PHD programme research “Design, simulation and control of hybrid ventilation systems in high energy performances buildings” founded by Elithis Groupe in parternship with the LEPTIAB of La Rochelle.

This paper presents the effect of specific future climate changes scenarios on the resilience of the refurbishment of a 1960s office building in suburban London. A model of the building was created and simulated using IESVE to predict current energy consumption calibrated with operational energy data. Energy efficient improvements were incorporated which mainly consist of improving the insulation and air-tightness of external envelope, reducing solar and internal gain and utilising natural ventilation during the day and night for improving thermal comfort in the summer.

This paper deals with air-soil heat exchangers used for heating or cooling airflows used for ventilation of buildings. Basing on a previously published analytical solution concerning heat charge and discharge around an array of buried pipes, it is shown how convective air/pipe and diffusive pipe/soil heat exchange are combining, and how the characteristic exponential amplitude-dampening along the pipe is achieved. The main result consists in dimensioning guidelines, in terms of relations between airflow and pipe length necessary for complete dampening of yearly or daily amplitude.

In France, starting on January 1st, 2013, a minimum airtightness value for all residential building will be required by the energy performance regulation (RT 2012). It will be compulsory to justify for any new residential building that its airtightness is below 0.6m3/h.m² at 4 Pa (Q4Pa_surf) for single-family houses and 1 m3/h.m² for multi-family buildings. 

Through the experiences gained by building a sufficient number of air-tight buildings, the author will illustrate the ease of detailing and constructing an air tight building. Using parallels to conventional building typologies, the methods of making an air-tight building enveloppe will be explained. The presentation will be divided into following chapters:

1. Precicious building methodology. 

At the end of 2010, two manufacturers have commissioned an independent engineering firm to carry out a cost-benefit analysis of air-tightness in ventilation. The study report uncovers the clear return of investment in class C air-tight ventilation systems in Belgium.
The study comprises:

Enhancing the energy efficiency of buildings imposed by global warming and by the perspective of fossil fuel dwindling requires new technical solutions, more efficient. The race for efficiency directly affects ventilation and air tightness of buildings, the main potential causes of heat loss in homes. If heat recovery is emerging as an effective solution to meet energy performance and indoor air quality in climates with harsh winters, some other solutions appear to be very efficient in moderate climates.

The thrust of airtightness specification and testing is derived from energy considerations. The application to healthcare buildings and specialist laboratory facilities embodies the same principles but derives the appropriateness of the criteria with reference to [a] producing controlled and controllable cascading pressure zones and [b] specifying or quantifying the potential exposure in the event of failure of mechanical ventilation.

During the recent decades, energy consumption of buildings, together with the costs for operation, has gained increasing concern. HVAC systems stand for a significant share of the total energy consumption in buildings. Demand-controlled ventilation (DCV) has proved to be an efficient system that gives opportunity to strongly reduce energy consumption, especially when contamination loads or temperature load vary during the operating hours. 30-60% energy reduction can be expected by applying proper DCV.