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The goal of this paper is to quantify the impact of weather-induced and altitude-induced barometric pressure variations on the cooling capacity measurement of hydronic coils in room fan coil units....

Air conditioning engineers design the inlet or outlet position of a fan coil unit (FCU) system according to thermal comfort and cost. However, the effect of the position on fire growth has not been...

The purpose of this study was to provide in situ field data on fan/motor efficiency and fan static pressure differentials for the fan/motor combinations used in fan coil units. Measurements were ma...

Salt hydrate for application as secondary refrigerant in the air-conditioning system are selected based on the slurry forming according to the evaporator temperature 5°C–12°C. Research development of salt hydrate for application is done in three stages, namely; the study of the properties, flow, and heat transfer characteristics, also applications in air-conditioning systems. The study of the properties of the phase change materials is in the form of latent heat, freezing and melting temperature, thermal stability properties, viscosity, and rate of corrosion. The study of flow and heat transfer characteristics determine the effect of salt hydrates on the pressure drop and heat transfer in a heat exchanger. Studies on the application of the air-conditioning system is made to use a type of cooling room air-handling units and fan coil unit. The results of the researches for each of two stages are described in the discussion of the current article. The characteristics of salt hydrates from Na2HPO4 and CaCl2 a...

On-site investigations show that an asynchronous load feature would greatly influence the operation of water systems for centralized air conditioning. However, the manner of defining the load feature and relating it to its influence quantitatively is still unclear. This article quantitatively describes the asynchronous load demand feature and reveals its relationship with the loss of pump power and heat transfer ability in a centralized air-conditioning water system. The Lorenz curve and the Gini index are introduced in this study and used as indices to depict load features. For a large-scale use in office buildings, shopping malls, and other buildings, the fan coil unit and the variable air volume systems are investigated in this study. The loss of pump power on valves and heat transfer ability under different load profiles are analyzed. This study develops a new perspective of analyzing load patterns and quantitatively explores reasons for the resulting losses in pump power and heat transfer ability in ...

In this paper, we present a generative design approach using constraint-based programming to handle the space configuration for ceiling mounted fan coil systems in buildings. This work utilises and builds on the result from previous projects presented in Medjdoub et al. [(2003). Generation of variational standard plant room solutions. Automation in Construction, 12(2), 155–166] and Medjdoub [(2009). Constraint-based adaptation for complex space configuration in building services. ITcon, 14, 724–735.]. In Medjdoub [(2009). Constraint-based adaptation for complex space configuration in building services. ITcon, 14, 724–735], we have presented a hybrid approach using case-based reasoning and constraint satisfaction problem approach to deal with the space configuration and pipe routing of complex design problems for ceiling mounted fan coil systems in buildings. One of the limitations of the aforementioned approach is that the solution generated is defined only geometrically. In this work, we have redefined t...

In this paper, an economic analysis of systems adopted as the perimeter zone system in office buildings such as convector, fan coil unit(FCU) and fan powered unit(FPU) was performed, with the variable air volume(VAV) system applied in the interior zone. The initial cost of each alternative, such as the construction cost of the air conditioning system, was determined by planning and design, and energy cost as running cost was calculated on the basis of the energy consumption of each system using a computer simulation. Economic analysis was performed using life cycle cost(LCC), with the present value method for the air conditioning system in the perimeter zone. The results show that FPU is the most economical air conditioning system. When VAV is applied to the interior zone, LCC of the FCU is reduced by 6% and the cost of FPU is reduced 9% less than that of the convector system.

For heating, ventilating, and air-conditioning (HVAC) systems for commercial buildings, the cooling coils in air-handling units (AHUs) account for a significant fraction of total building energy consumption and have a major impact on comfort conditions and maintenance costs. Development of cost-effective advanced control strategies will enhance the performance and efficiency of AHUs. The control design process can be greatly facilitated with simulation on a high-fidelity dynamic model prior to experimental validation and implementation. This paper presents a dynamic model for a chilled-water cooling coil. The model development was based on Dymola and Air Conditioning Library with some revision on heat exchanger modeling. For chilled-water cooling coil modeling, the major challenges include the variation of coil surface conditions under flow rate changes and partially-dry-partially-wet operations. This study proposes a dynamic coil model that is capable of predicting cooling performances under fully dry, p...

In a warm environment air movement with elevated velocity is a well-known cooling strategy. The local air movement is typically generated by cooling fans (e.g. ceiling fan, table fans, etc.). Appearance, power input and price are the main parameters considered today when purchasing cooling fans, while their cooling capacity and efficiency of energy use are unknown. A new index is introduced, named “cooling fan efficiency index” defined as the ratio between the cooling effect (measured with a thermal manikin) generated by the device and its power consumption. The index was determined for a ceiling fan, a desk fan, a standing fan and a tower fan in a real office at three room air temperatures and at different fan speed levels. The results revealed that the index is sensitive enough to identify differences in the performance of the cooling devices. A standard method(s) for testing fan cooling effect and index(s) for determination of their efficiency, such as the proposed in this study cooling fan efficiency index, need to be developed. The cooling fans generate a non-uniform velocity field around occupants which cannot be described with a single air velocity value. Therefore it is not clear how to apply in practice the recommended in the present standards eleveted velocity in a warm environment. The standards need to be revised.

The objective of this research was aimed at conducting an experimental investigation to study the heat sink performance of a new rectangular fins array. Various operating conditions were considered, namely the distance between the fan and the fins, varied from 0 mm to 40 mm, heat supplied to the sink and the fan voltage. It was concluded that a fan installed at 30 mm height from the fins is recommended as the hot side temperature was the lowest. Next a pre-experimentation of small scale prototype of thermoelectric Dehumidifier (TED) was designed and constructed. It was composed of two thermoelectric (TE) cooling modules, MT2-1, 6-127, (two in serial) mounted between the rectangular fin heat exchangers with dimension 140 × 240 × 35 mm. The hot side was cooled by a ventilation fan whereas the air flow on the cold side was free convection. The effect of position of fan was investigation experimentally. Preliminary tests confirmed the good performance of the hot heat sink design for the intended thermoelectri...

Fans save energy when they complement a regular air-conditioning system and move air at an acceptable speed without compromising thermal comfort. They allow a higher set-point temperature, thus reducing A/C operating hours and saving electrical energy. The study presents derivation for the comfort thermostat air temperature setting function of air velocity for typical bed room conditions. The typical profile of air flow pattern due to wall mounted oscillating fan is shown for representative bed room lay out. The impact of a wall-mounted fan on the energy consumption and A/C sizing savings of a bedroom were investigated using energy simulation program, EZDOE 2.1D. The study confirms that fan application achieves significant savings in annual electricity use and reduces AlC sizes, operating hours and extends the neutral hours.

Fuzzy models and controllers are represented by if-then rules and thus can provide a user-friendly and understandable representation of combined quantitative and qualitative description. The qualitative rules result in a quantitative non-linear controller well suited to nonlinear systems controlling thermal comfort with vague defined objectives as fan-coils used in solar energy systems. The fuzzy models are achieved through identification by varying the inputs so that the fan-coil reaches the states encountered in normal operation. These models may be used for control or for simulation. On its domain of validity, the fuzzy controller behaves better then a classical controller. In fact, the main advantage of fuzzy controller is the easiness of introducing operating modes and poor defined objectives specific for solar energy systems such as freeze and over-temperature protection, or draining.