Humidity Control System Research Articles

High energy efficiency desiccant assisted automobile air-conditioner and its temperature and humidity control system

The energy efficiency is of importance in air conditioning systems for automobiles. The present article provides a new type air conditioning system for automobiles in which energy loss is small in comparison with the previous system. In the system, a desiccant is installed in the air conditioning system for controlling both temperature and humidity. The control is performed by an electromagnetic control valve, which controls an inclination of the rotating plate of a compressor. It is difficult to control both temperature and humidity precisely, because there are some delays in the control due to the time of heat exchange and that of coolant flow from the actuator (electromagnetic valve) to the evaporator. In order to have precise control, this article also presents a method of control with consideration of control delays. The energy of our system is compared with that in the previous conventional system in the same condition. It is shown that our controlled results and energy efficiency are better than those in the previous system.

Adaptive shaping system for both spatial and temporal profiles of a highly stabilized UV laser light source for a photocathode RF gun

We have been developing a stable and highly qualified ultraviolet (UV) laser pulse as a light source of an RF gun for an injector candidate of future light sources. Our gun cavity is a single-cell pillbox, and the copper inner wall is used as a photocathode. The chirped pulse amplification (CPA) Ti:sapphire laser system is operated at a repetition rate of 10 Hz. At the third harmonic generation (central wavelength—263 nm), the laser pulse energy after a 45 cm silica rod is up to 850 μJ/pulse. In its present status, the laser's pulse energy stability has been improved down to 0.2∼0.3% at the fundamental, and 0.7–1.4% (rms; 10 pps; 33,818 shots) at the third harmonic generation, respectively. This stability has been held for 1 month continuously, 24 h a day. The improvements we had passively implemented were to stabilize the laser system as well as the environmental conditions. We introduced a humidity-control system kept at 50–60% in a clean room to reduce damage to the optics. In addition, we prepared a deformable mirror for spatial shaping and a spatial light modulator based on fused-silica plates for temporal shaping. We are applying both the adaptive optics to automatic optimization of the electron beam bunch to produce lower emittance with the feedback routine. Before the improvements, the electron beam produced from a cathode suffered inhomogeneous distribution caused by the quantum efficiency effect, and some pulse distortions caused by its response time. However, we can now freely form any arbitrary electron beam distribution on the surface of the cathode.

RELATIVE HUMIDITY CONTROL IN REFRIGERATED FACILITIES

Air relative humidity (RH) significantly affects the storage life and quality of horticultural products. RH is determined by the balance between rates of moisture (latent heat) entry into and removal from the air. Conditions in a small walk-in cool store and its associated refrigeration system were monitored to validate moisture transport models, investigate the effect of design and operating factors on RH, and explore the effect of coil defrost frequency on store performance. Store RH was accurately predicted. Measured results and model predictions showed important ways of influencing RH: control of sensible heat entry (e.g. insulation levels), management of air infiltration rates, design and operation of cooling coils with appropriate air-to-refrigerant temperature difference, choice of temperature control systems, and selection and equilibration of packaging materials. Optimisation of air RH by such methods allows cold chain improvement without unnecessary expense on dedicated humidity control or advanced packaging systems. At high defrost frequency, energy use increased and temperature control was poorer due to the pull-down after each defrost. At low frequency, RH was lower, energy use increased and temperature control was poorer due to coil performance decline and longer duration defrosts. For the system studied, a defrost frequency of 8 to 12 hours was optimal.

Discriminative Detection of Volatile Sulfur Compound Mixtures with a Plasma-Polymerized Film-Based Sensor Array Installed in a Humidity-Control System

We demonstrated the discrimination of volatile sulfur compound mixtures with different mixing ratios by using an array of the plasma-polymerized film (PPF)-coated quartz crystal resonators. The PPF sensor array, which contains PPFs prepared from amino acids and synthetic polymers, exhibited different response patterns to mono or mixed volatile sulfur compounds (VSCs) (hydrogen sulfide and methanethiol) under a dry environment. The sensor array was installed in a desktop-size relative humidity controller. The relative humidity and temperature conditions of the sample flow to the sensor cell were equalized to those of the inner atmosphere of the sensor cell based on the concept of the two-separate-temperatures method. In this way, the baseline drift of PPF sensor response caused by the introduction of a highly humid sample was successfully suppressed. We compared the sensor array responses under the controlled humidity conditions. Presorption of water molecules by PPFs caused a decrease of sensor sensitivity, but the films still had the ability to discriminate sub-ppmv VSC mixtures having 6:1, 1:1, and 1:6 mixture ratios of hydrogen sulfide and methanethiol.

Heat stroke in an incubator: an immunohistochemical study in a fatal case

The authors report the unique case of an 8-day-old infant succumbing to heat stroke caused by an abnormal increase of the environmental temperature in an incubator. At postmortem examination, second-degree burns were detected, and macroscopic and microscopic findings were typical for a heat-related death. An immunohistochemical study was performed. At the same time, a detailed examination of the incubator was conducted, revealing a malfunctioning of the temperature and relative humidity control system. We suggest that the diagnosis of heat stroke has to be confirmed on the basis of a detailed postmortem examination and a complete immunohistochemical investigation of heat shock proteins, molecules produced acutely in response to heat stress.

Technical review of the Laboratory Biosphere closed ecological system facility

Laboratory Biosphere is a 40 m 3 closed life system that commenced operation in May 2002. Light is from 12,000 W of high pressure sodium lamps over planting beds with 5.37 m 2 of soil. Water is 100% recycled by collecting condensate from the temperature and humidity control system and mixing with leachate collected from under the planting beds. Atmospheric leakage was estimated during the first closure experiment to be 0.5–1% per day in general plus about 1% for each usage of the airlock door. The first trial run of 94 days was with a soybean crop grown from seeds (May 17, 2002) to harvest (August 14, 2002) plus 5 days of post-harvest closure. The focus of this initial trial was system testing to confirm functionality and identify any necessary modifications or improvements. This paper describes the organizational and physical features of the Laboratory Biosphere.

Measurement of Percutaneous Uptake of 2-Methoxy Ethanol Vapor in Humans

Absorption of vapors through skin has been largely ignored in occupational health, although for ethylene glycol ethers this route of exposure could be more important than inhalation. We used an automated concentration and humidity controlled system to measure real-time percutaneous absorption of 2-methoxy ethanol (ME) vapor in seven volunteers. The exposure concentration (300 +/- 10 ppm or 25 +/- 0.5 ppm), humidity (80 +/- 2%), and temperature (27.5 +/- 0.5 degrees C) were controlled throughout the experiments. Uptakes during 4-hour single-arm exposure at 25 ppm and 300 ppm were 7.0 mg and 65.3 +/- 25.0 mg, respectively, with corresponding uptake rates of 1.36 micrograms/cm2/hr and 13.2 +/- 5.0 micrograms/cm2/hr. Percutaneous absorption was consistent and unsaturated during exposure. Because the permeability constant of ME vapor (14.0 +/- 5.3 cm/hr) was much higher than that of many widely used organic chemicals, we concluded that vapor absorption through skin is a significant contributor to overall ME exposure.

MEASURING FACILITY FOR (SHORTWAVE) RADIATION TRANSMISSION OF CONDENSATION COVERED GREENHOUSE CLADDINGS

To investigate the effect of water drops on the Photosynthetically Active Radiation (PAR) transmittance of greenhouse cladding materials, an experimental unit was built. A light-tight double climate room (hot box/cold box), equipped with a temperature and humidity control system, permits the controlled production of condensation on any cladding material. By means of a parallel light source inside the cold box and an integrating sphere in the hot box, it is possible to measure the PAR transmittance for several cladding materials, for the several phases of the condensation and evaporation process, and for several orientations of the material under investigation: vertical or inclined. Preliminary results for experiments on vertical polyethylene (PE) and glass covered with condensation without runoff resulted in a decrease of the PAR transmittance at normal incidence by about 22 and 3%, respectively. When compared to the transmittance curve for dry PE, the one for wet PE was found to be less steep for incidence: angles up to 60 degrees and to agree best with the average of simulated curves for cap shaped drops with contact angles between 40 and 90 degrees.

New Developments in Instrumentation for X-ray and Neutron Fibre Diffraction Experiments

New instrumentation has been developed for use in X-ray and neutron fibre diffraction studies to provide automated control of sample position, orientation and ambient relative humidity. A sample mount system has been constructed for the Keele fibre diffraction camera on beamline 7.2 at the Daresbury Laboratory synchrotron radiation source. This allows the sample position and orientation to be controlled remotely, without disturbing the sample environment or the detector, and permits the implementation of efficient data-collection strategies. The system can be used to record entire datasets without incurring any loss of data in the meridional region of the diffraction pattern and has also been used to record three-dimensional datasets from fibres exhibiting `double orientation'. The design incorporates a translation feature so that the effects of radiation damage during data collection can be minimized. An automated humidity control system has also been constructed and can be used in either X-ray or neutron fibre diffraction studies where the water content of samples is a critical parameter and careful control of the relative humidity of the sample environment is required. This system allows the relative humidity to be controlled according to a pre-programmed set of instructions and alleviates some of the common problems that are encountered with conventional methods that require the use of saturated salt solutions. The system is currently installed on instrument D19 at the Institut Laue–Langevin, Grenoble. Results illustrating the application of these facilities in high-angle fibre diffraction studies of DNA are presented.

Humidity Control System with Adsorption Materials.

The present study introduces a humidity control apparatus which can hygienically and automatically maintain an appropriate humidity level of indoor air without either a water supply or a drainage system. In humidification using this apparatus, the desiccant takes up water vapor from the outdoor air in the adsorption process, and releases it indoors by desorption. Therefore, no water supply is required. An apparatus having no water supply is hygienic, because it does not propagate bacteria and does not scatter the calcium and magnesium salts found in water. In dehumidification using this apparatus, water vapor is removed from the indoor air by the desiccant and is released outdoors by desorption, eliminating the need for a drainage system. The absence of a drainage system also eliminates such problems as water leakage and installation.

A Humidity Control System with an Adsorption Material and Indoor Air Quality Improvement

A Humidity Control System with an Adsorption Material and Indoor Air Quality Improvement

Effect of environmental humidity on the transformation pathway of nitrofurantoin modifications during grinding and the physicochemical properties of ground products.

The effect of humidity on the physicochemical properties of nitrofurantoin anhydrate and monohydrate during grinding in a humidity-controlled system was investigated using X-ray diffraction analysis, IR spectroscopy, thermal analysis and scanning electron microscopy. Anhydrate and monohydrate were transformed into a noncrystalline solid and a stable monohydrate, respectively, during grinding in a closed system. During grinding in an open system, in which the humidity level of the air was controlled (5, 50 and 75% r.h.), the anhydrate absorbed moisture from the supplied air and water content was increased at 75% r.h.; thereafter the compound was transformed into monohydrate II. The anhydrate did not absorb at 5 or 50% r.h. and was transformed into a noncrystalline solid. Monohydrate I desorbed crystal water during grinding at 5% r.h. and was transformed into a noncrystalline solid. However, monohydrate I was transformed into monohydrate II at 50 and 75% r.h. without desorption of crystal water. These results suggest that the solid-state transformation of nitrofurantoin during grinding depends upon the environmental humidity.

Humidity control system for a controlled atmosphere container comprises cooler for compressed air filter, storage reservoir, means to increase humidity and regenerative and cooling heat exchangers : Litton Systems Inc. EP-48913; 10 June 1992

A rapid and accurate method based on automated immunoaffinity magnetic beads (IMB) clean-up and ultra-performance liquid chromatography with fluorescence detection (UPLC-FLD) was developed for the determination of ochratoxin A (OTA) in cereals and oils. The main parameters affecting the method were studied in detail. Under optimized conditions, the recoveries of spiked analytes at four different concentrations were ranged from 86.3 to 95.4% and the inter-day relative standard deviations were below 7.9%. Coupling with UPLC-FLD allowed the limits of detection and quantification to be 0.24 and 0.80 μg/kg, respectively. The results demonstrate that the proposed method is reliable to determine OTA in cereals and oils. This novel protocol utilizes a simple and automatic sample pretreatment procedure for high-throughput and rapid clean-up of OTA in complex samples. Moreover, this method improves the performance of OTA analysis in cereals and oils. By consuming less time, cost and labor, as well as fewer errors from operation, the developed protocol overcomes the drawbacks of traditional column-based clean-up methods and thus offers a great prospect for OTA analysis mainly in the applications of food safety and public health protection.

Temperature and humidity control system in a lunar base

An increasing number of lunar base construction programs are in the process of developing lunar resources such as helium 3. The objective of the present work is to evaluate the temperature and humidity control system, which will allow man to live and work on the moon while developing lunar resources. The results of thermal load calculation show that the load of electric lighting is a 80 to 90% of the cooling load in the habitat module and that only the cooling function is required for temperature control. Due to this, a fluorocarbon refrigerant heat pump system was selected to satisfy reliability, energy consumption, size and weight requirements for the lunar base equipment. According to the load calculation, occupants will feel discomfort due to radiant heat from lighting fixtures. To resolve this problem, an air conditioning system, used in combination with forced convective cooling and panel cooling on the ceiling, was adopted in the living space. Moreover, the experiment on the ground was carried out to evaluate the effects of panel cooling.

Temperature and Humidity Control System in a Lunar Base

Temperature and Humidity Control System in a Lunar Base

Temperature and Humidity Control in Cotton Classing Offices

ABSTRACT D EPENDABLE temperature and humidity control systems in cotton classing facilities can reduce varied classing of similar grade cotton. This study examined the dust concentrations and effectiveness of environmental control systems at three USDA-AMS cotton classing facilities. The hygroscopic nature of cotton fibers and the moisture and heat generated by workers influenced the temperature and humidity fluctuations recorded within the facilities. Temperature and humidity levels increased near the return air register in each facility. Total dust and microdust contents were determined for each facility. Recommendations were developed for improving temperature and humidity control systems at classing facilities.

X-Ray Study Of Freely Suspended Films Of A Multilamellar Lipid System

Abstract We report the first x-ray scattering measurements from freely suspended lipid (DMPC)-water multilayer films. By combining several techniques, we are able to grow stable, oriented films of various thicknesses (∼102 to 104 A) in a controlled temperature (0°C to 80°C) and humidity (0% to 100%) environment. A specially designed film holder allows both transmission and reflection x-ray measurements. Very importantly, the humidity control system allows us to construct the temperature-chemical potential phase diagram in addition to the normally studied temperature-concentration phase diagram. Our most important results are as follows. First, we find a metastable Lα phase in bulk DMPC-water mixtures when the water concentration is between 30 and 40 weight percent, and second, from the variation of the interplanar peak position as a function of concentration and chemical potential, we are able to deduce the functional form of the interaction force between layers in the Lα. phase. This form is found to be ...

The development of a local humidity control system

Micro-environments are not the focus of this bibliography, but any discussion of practical climate control measures must consider the use of micro-environments for artifacts especially suspectible to changes in relative humidity. It explaines the design of the basic climate controlled showcase using silica gel.

The development of a local humidity control system

The development of a local humidity control system

An Uncommon System for Manual Control of Olfactometer Air Relative Humidity1

Work done in this laboratory on mosquito attractants and repellents often involves the use of 8 dual-port olfactometers (Schreck, Gouck & Smith, 1967, J. Econ. Entomol. 60 : 1188–90). The olfactometers are supplied with a 661 liters/sec (1400 cfm) flow of conditioned, outside air, the humidity of which has been generated by a water spray and controlled by a mechanical, hair-type humidistat. Because of the original systemʼs excessive set point drift and control band width (± 10% RH), a new humidity generation, monitoring, and control system was developed.