This paper describes a methodology for improving individual thermal comfort in an officebuilding without increasing energy consumption. Our approach is based on the observationthat an individuals preferred temperature is not a precise value, but a range around apreferred value. We take advantage of this to optimize the temperature settings of eachoccupants personal space to minimize the overall energy use. We have employed a nonlinearprogramming approach to improve individual thermal comfort without increasing energyconsumption, even possibly saving energy.

Entrance of snow into the HVACsystemsis common problem in the arcticandsubarcticclimates and may cause moistening or wetting of filters and outdoor air chambers whichpromotes microbe growth. Blocking the filters also increases pressure drop or even damages thefilters. The design features and velocity of air in the outdoor air intake play key role when theproblems occurs. To eliminate the snow entrance into the HVACsystemsthe face velocity of theoutdoor air shall be below 1 m/s at the intake louvre.

The effectiveness of UV radiation lamps in order to reduce fungal contamination of HEPA filters, to extend filter efficacy and to reduce maintenance costs, is experimentally studied by means of a dedicated air conditioning unit. An experimental HVAC system, with HEPA filters and UV-C lamps (?=254 nm), was built. Two experiments were performed. After disinfection and control of airtightness, the internal surface of the HVAC system was contaminated (1) with A. niger spores and (2) with Actynomices. Temperature level was 300 K and Relative Humidity (RH) ranged from 30-90%.

Cleaning ventilation system ductwork has been a topic of controversy for several years. Guidance documents are available for duct cleaning, but uniformity in application of remediation and cleaning methods is inconsistent in many cases. Means and methods for cleaning range from high-volume negative pressure vacuum cleaning of residential ductwork ...to use of sanitizing agents on the interior of galvanized ducts...to ultraviolet germicidal irradiation for treatment of re-circulated air and control of infectious viral aerosols in operating room suites.

Since the study by P.O Fanger (1988) [1] we know that the Heating Ventilating and AirConditioning (HVAC) system could be responsible for a large amount of indoor air pollutionand Sick Build Syndrome (SBS). The pollution could become from filters, cooling coils anddust accumulated on duct surfaces in systems with poor maintenance.While the importance of maintenance of air handling units and replacement of air filters iswell recognized in Portugal, the cleanliness of ducts is sometimes forgotten.

The sources of man-made mineral fibres (MMMFs) settled on furniture surfaces and in supply air were determined in an office building. The impact of renovation on indoor air and the perception of air quality by the occupants were studied. Renovation improved the air-tightness of the inner parts of structures. Settled MMMFs were collected with gelatine tape by pressure and deposition techniques. MMMFs in supply air were collected using the filter installed to the supply diffuser.

Man made mineral fibers (MMMFs) that can cause irritation in upper respiratory tract, eyesand skin, can be emitted to indoor air from the HVAC system. A Finnish project was set up tomeasure fiber emissions and to develop design and materials of the HVAC systems toimprove indoor air quality. Within the project laboratory tests and field measurements werecarried out.As a result, new methods of testing the emission rates of the MMMFs from HVACcomponentshave been developed. With these methods HVAC-components can be classifiedwithin the Finnish Indoor Air Classification.

The published REHVA guidebook provides comprehensive uptodateinformation aboutdesign features, criteria for cleanliness, inspection and cleaning instructions of ventilationsystems. The guidebook is aimed at practitioners, designers and those who are setting criteriafor cleanliness of ventilation systems. The design practice includes guides to construct a cleanventilation system and which cleanliness can be maintained during whole lifetime of thebuilding.

The objectives of this study are to reproduce in the laboratory different levels of cleanliness innon-porous ducts of HVAC systems, to compare a new method for sampling surface dust inducts with those methods cited in the literature, to compare the numerical evaluation methodto the visual method, and to propose objective cleaning initiation criteria.

The relationship between construction activities and an increased risk of microbial contamination and degradation of air quality in new building construction and renovation projects was studied. Poorly designed or installed ventilation systems and inferior workmanship during construction were determined to have an adverse impact on the performance of the building ventilation system. This presentation will provide guidelines to protect HVAC system components during building construction and renovation projects and for building commissioning procedures for building ventilation systems.