A range of techniques are available to measure the moisture content of building fabrics. Indeed a thermal dual-probe has been successfully developed by the authors for measuring the moisture content of building fabrics in situ. However, the dual-probe technique has limitations due to the fact that two, small diameter, parallel holes must be drilled for inserting the dual-probe into the material to be measured. It is difficult to drill such holes accurately in many building envelops and thus, such a dual-probe may be most useful for relatively ‘soft’ materials, such as aerated concrete. This paper describes the ‘proof of concept’ of an innovation that surmounts this problem via the development of a ‘pad’ sensor. Instead of the ‘traditional’ dual-probe approach, the heater and temperature sensor are fixed to the surface of a thermally insulated block. The most important benefit of the pad sensor approach is that no holes are required to be drilled in the material of interest. The moisture content of the building envelops can be measured simply by placing the pad sensor against the wall surface. Extensive finite element modelling was carried out to design the pad sensor and a prototype built. Initial experimental work was then carried out to test the pad sensor – the measured moisture content obtained from the pad sensor was compared with the results of a series of gravimetric analyses. Encouraging agreement between the two methods was obtained.

Practical application: A thermal dual-probe has been successfully developed by the authors for measuring the moisture content of building fabrics in situ. However, the dual-probe technique has limitations due to the fact that two, small diameter, parallel holes must be drilled for inserting the dual-probe into the material to be measured. This paper describes an innovation that surmounts this problem via the development of a ‘pad’ sensor. The moisture content of the building envelopes can be accurately measured simply by placing the pad sensor against the wall surface. The pad sensor offers a non-destructive method to measure the moisture content and thus is potentially attractive for applications where this issue is of importance e.g. monitoring the moisture content of historical buildings.

The accuracy of model predictions plays an important role in model-based applications. However, mathematical models exhibit more or less uncertainties. In this study, a full-scale dynamic model of a two-zone variable air volume heating, ventilation, air-conditioning and refrigeration (VAV-HVAC&R) system is considered. A fuzzy set-based uncertainty analysis method is employed to study the effects of uncertain parameters on HVAC&R system modelling and describe the associated inaccuracies in HVAC&R system model predictions. In this study, uncertain parameters, i.e. zone cooling loads, heat transfer coefficient, chilled water and condenser water mass flow rate and water temperature at condenser inlet are considered and treated as fuzzy parameters. The extended transformation approach is used to evaluate the uncertainties in the model outputs including time history of the zone temperature, discharge air temperature, temperature of chilled water and condenser water. The upper and lower bounds of these outputs are determined for each -cut level, and the probability distributions of the outputs are presented.

Practical applications: Compared to monitoring of real systems, model-based simulation provides an easier, faster and cheaper substitute to gather operating information and evaluate operating performance of HVAC&R systems. However, simulation results obtained from traditional methods by which model equations are solved with predetermined values cannot accurately represent the possible responses of the system. Thus investigating the probability distributions of the simulation results under parameter uncertainties is very important to ensure the accuracy of the model predictions. The fuzzy set-based uncertainty analysis method presented here helps in identifying the upper and lower bounds of model outputs by quantifying the range within which the responses fall under parameter uncertainties. Also, the contributions of individual uncertain parameters to the uncertainties of model outputs help in identifying the impact parameters.

The experiment providing data on the energy demand and air exchange in the flat located in the multifamily building is presented in the paper. The measurement was carried out during 3 weeks in winter. The total energy consumption necessary for flat heating was measured continuously. During the same time air change rate in the flat was measured by means of tracer gas concentration decay methods. After measurements were finished the energy demand and ventilating airflows were calculated assuming the same weather data variation as measured during the experiment, using the ESP-r software. Contam program was used for the air infiltration simulation, giving more detailed results about the ventilation airflows within the tested object. Comparison was made between numerical results and measured data over the given cycle and a good correlation of results has been achieved.

Practical applications: Simulation methods can be an alternative to the assessment of energy consumption or heat demand in buildings when the direct measurement is impossible or difficult. A good agreement of simulation and measurement results is reached when the average values of the results are compared for a longer period of time.