A topology approach to overcome the pore size/volume trade-offs for autonomous indoor humidity control

Autonomous indoor humidity control is gaining more and more attention but is limited by the trade-offs among pore volume,pore size and water stability of water adsorbents.We solve this problem by using a unique coordination network topology combined with hydrolytically stable M(Ⅲ)carboxylate clusters.By extending the ligand length from 9.0 to 11.2 and 13.7?,the pore volume significantly increases from 0.99 to 1.40 and 1.78 cm^(3)g^(-1),which proportionally increases the saturated water adsorption capacity.Meanwhile,the pore size slightly increases from 10.4 to 11.0 and 13.5A,which restricts the isotherm inflection pressure and hysteresis width to meet the requirement of indoor humidity control.Large single-crystals suitable for Xray diffraction studies were obtained by using Fe(Ⅲ)salts,while isostructural frameworks with sufficiently high water stabilities were synthesized by using Cr(Ⅲ)salts,which offer record working capacity of 0.90 and 1.10 g g^(-1)for indoor humidity control.

A Comparison of Relative Humidity between Two Swedish Buildings with Different Ventilation Solutions

This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which constitutes a representative climate zone with respect to Swedish conditions. An important factor for the indoor environment, which affects human health and well-being, is the level of the relative humidity, RH (%). Research studies show that the healthiest level should be in the range of 40% - 60%. Surveys have revealed that about 70% of the employees at Swedish offices, schools and kindergartens experience that the air is too dry during the winter season. Previous studies show that the level of relative humidity in the indoor environment influences the prevalence of respiratory infections and allergies. The purpose of this study is to investigate how the relative humidity differ between the two buildings, and if this may be a cause of the health problems that users are affected by. During many years, users have complained about the environment in the building with mechanical ventilation and that they suffer from health problems. The method used in the study is air measurements of the two parameters, relative humidity and air temperature in the two buildings using data loggers. The indoor environment is affected by the outdoor climate and therefore instruments are placed outdoors to record seasonal variations. The measurements were carried out during the period October 2014 to September 2015 to include all of Sweden’s four seasons with completely different climatic conditions. The results of this study show that the relative humidity in the mechanically ventilated building is consistently significantly lower than in the building with natural ventilation whatever the time of year and temperature indoors. This study shows that mechanical ventilation in buildings affects the indoor environment negatively with respect to human health during most time of the year and this fact must be taken into consideration for the existing as well as the planning of new ventilation systems.

Indoor Air Environment—Hygienic Factors and Limits

Complaints on the indoor environment of the residents in recent decades have become a common problem in the Swedish housing. The buildings themselves are said to be the cause of problems, and it is given a vague picture of both the exposure and the effect of the problems. The symptoms that residents and users state are often common in the population such as headache, fatigue, mucosal disorders and skin problems. It must be considered that the air that people routinely inhale contains impurities of various kinds, both in- and outdoors. An important source of contamination indoors is the microorganisms that are pathogenic, so called agents. Examples of infectious agents are viruses, fungi, bacteria and protozoa. The purpose of this project is to examine whether a physical measurement is possible to obtain for identifying a possible threshold level of air pollution in the indoor environment. In this study, carried out through physical measurements, the results show major deficiencies in the Swedish school environment. If we study the emissions in the important health-related size range of particles larger than 5.0 microns, before and after measures, the environmental benefits are clarified since over 90% of contaminants larger than 5.0 microns have been eliminated.

Fast prediction for multi-parameters(concentration,temperature and humidity)of indoor environment towards the online control of HVAC system

Heating,ventilation and air conditioning(HVAC)systems are the most energy-consuming building implements for the improvement of indoor environmental quality(IEQ).We have developed the optimal control strategies for HVAC system to respectively achieve the optimal selections of ventilation rate and supplied air temperature with consideration of energy conservation,through the fast prediction methods by using low-dimensional linear ventilation model(LLVM)based artificial neural network(ANN)and low-dimensional linear temperature model(LLTM)based contribution ratio of indoor climate(CRI_((T))).To be continued for integrated control of multi-parameters,we further developed the fast prediction model for indoor humidity by using low-dimensional linear humidity model(LLHM)and contribution ratio of indoor humidity(CRI_((H))),and thermal sensation index(TS)for assessment.CFD was used to construct the prediction database for CO_(2),temperature and humidity.Low-dimensional linear models(LLM),including LLVM,LLTM and LLHM,were adopted to expand database for the sake of data storage reduction.Then,coupling with ANN,CRI_((T)) and CRI_((H)), the distributions of indoor CO_(2) concentration,temperature,and humidity were rapidly predicted on the basis of LLVM-based ANN,LLTM-based CRIm and LLHM-based CRM respectively.Finally,according to the self-defined indices(i.e.,E_(V),E_(T),E_(H)),the optimal balancing between IEQ(indicated by CO_(2) concentration,PMV and TS)and energy consumption(indicated by ventilation rate,supplied air temperature and humidity)were synthetically evaluated.The total HVAC energy consumption could be reduced by 35%on the strength of current control strategies.This work can further contribute to development of the intelligent online control for HVAC systems.

Water dissipation mechanism of residential and office buildings in urban areas

Indoor humidity directly impacts the health of indoor populations. In arid and semi-arid cities, the buildings indoor humidity is typically higher than outdoors, and the presence of water vapor results from water dissipation inside the buildings. Few studies have explored indoor humidity features and vapor distribution or evaluated water dissipation inside buildings. This study examined temperature and relative humidity （RH） changes in typical residential and office buildings. The results indicate a relatively stable temperature with vary range of-4-1~C and a fluctuation RH trend which is similarly to that of water use. We proposed the concept of building water dissipation to describe the transformation of liquid water into gaseous water during water consumption and to develop a building water dissipation model that involves two main parameters： indoor population and total floor area. The simulated values were verified by measuring water consumption and water drainage, and the resulting simulation errors were lower for residential than for office buildings. The results indicate that bathroom vapor accounts for 70% of water dissipation in residential buildings. We conclude that indoor humidity was largely a result of water dissipation indoors, and building water dissipation should be considered in urban hydrological cycles.