Modern buildings usually have an air-tight envelope. Therefore mechanical ventilation is very often necessary. A crucial part of the system is the filter, which allows creating an atmosphere that is free of dust, aerosols, and pollen. As organic material accumulates on the filter surface, the risk of micro-organism growth rises. This may yield health issues especially for the occupants of buildings. The method was implemented in both a test rig and the HVAC system supplying different laboratories with fresh air in order to aggregate data for different abnormal and normal operation conditions. Subsequent considerations focuses on the test-rig measurements. The machine learning algorithm was trained successfully to detect anomalies of the filter behavior. Finally, the change intervals of the filter may be adapted to the real degree of pollution without the requirement for visual observation in order to provide best air conditions. This algorithm is part of a general strategy for machine-learning processes for HVAC systems.

Contrary to conventional air-conditioning systems in non-residential buildings, the air-flow conditions are almost never considered in ventilation systems for residential buildings. Both the air inlets and the outlets are usually located at unfavourable places. This situation culminates in large buildings with many flats, where simplest supply-air apertures are installed with respect to cost restrictions. With small air flow rates, the ventilation efficiency is very poor due to a lack of air mixture. In order to improve the situation, a new supply air aperture has been developed recently. The air flow rate is designed to vary with time, with a low auxiliary energy requirement, with clear maxima and otherwise reduced flow rate. Hence, the corresponding momentum was expected to improve the air mixture in the room. First measurements confirm that the transient flow conditions allow high intrusion depths and a good mixing of the air. The pulsating airflow reduces the risk of draughts and increases both ventilation efficiency and thermal comfort in the living area. Moreover, the energy efficiency is improved as the average air-flow rate can be reduced.

Both the sensible heat recovery and the combined heat and humidity recovery are state of the art. Of particular importance is the humidity recovery in winter season. The transfer of water vapor from the humidity-laden exhaust air to the very dry fresh air is very important for a good room air quality. However, all systems established on the market require that supply and exhaust air streams crosses within the device. Practical enthalpy recovery systems for plant concepts with local separation of supply and exhaust air are not available on the market until now. In order to close this gap, the ILK Dresden works on a R&D project. The objective is the development of a textile heat exchanger, which - integrated into circulatory composite systems - can transmit not only sensible heat but also humidity between spatially separated air streams. The functional principle is based on a liquid sorption process via semipermeable membranes. The current state of the development will be presented. Furthermore an outlook is given how it is intended to proceed in the project in further steps.

The pandemic spread of the SARS-CoV2 viruses is leading to the use of new ventilation concepts in Europe. One of these options is the usage of Mobile Air Cleaning Devices. These are used as an alternative to central HVAC-systems (Heating-, Ventilation- and Air Conditioning-systems) and reduce the load of pathogens in the room. However, there are still no consistent methods for evaluating the performances of such devices. Thatswhy the effect on the pathogens, the benefit to the room, and the influence thereof on the room occupants are nearly unknown.This paper presents the measurements and results of different devices in the range of 500 m³/h to 1500 m³/h and beyond. Attention is given to the applied methods to define the different characteristics. Specifically, the parameters of volumetric flow rate, electrical power consumption, sound power, separation efficiency, effect on pathogens, room air flow, draught risk, and effects in the room show the need for development.

In the context of this article, a caloric method for measuring the performance of alternating home ventilation devices (push-pull units) is presented. The simple and robust method provides both reliable and reproducible characteristic values. Based on this method, a test bench was developed and built. With this test bench the characteristic values (volume flow, heat recovery rate, temperature change rate) of series products can be measured. The aim of the investigation is the determination and evaluation of the possible parameters influencing the measurement. For this purpose, the parameters are illustrated on the basis of measured values from a defined test standard, consisting of a fan and electrical heating in a housing (so-called golden sample), as well as a pair of push-pull devices. As a result, suggestions for improvements to the previous procedure as well as approaches for further development are shown.