14-90 Atmospheric Air Enters the Evaporator of an Automobile Air Conditioner at a Specified Pressure, Temperature, and Relative Humidity

Total Page：16

File Type：pdf, Size：1020Kb

14-49 14-90 Atmospheric air enters the evaporator of an automobile air conditioner at a specified pressure, temperature, and relative humidity. The dew point and wet bulb temperatures at the inlet to the evaporator section, the required heat transfer rate from the atmospheric air to the evaporator fluid, and the rate of condensation of water vapor in the evaporator section are to be determined. Assumptions 1 This is a steady-flow process and thus the mass flow rate of dry air remains constant during the entire process (mmmaa12 a) . 2 Dry air and water vapor are ideal gases. 3 The kinetic and potential energy changes are negligible. Analysis The inlet and exit states of the air are completely specified, and the total pressure is 1 atm. The properties of the air at the inlet and exit states may be determined from the psychrometric chart (Fig. A-31) or using EES psychrometric functions to be (we used EES) Tdp1 15.7C Cooling coils Twb1 19.5C h1 55.60 kJ/kg dry air T2 =10C T1 =27C 0.01115 kg H O/kg dry air 1 2 2 = 90% 1 atm 1 = 50% 3 Condensate v1 0.8655 m / kg dry air 2 1 h2 27.35 kJ/kg dry air 0.00686 kg H O/kg dry air 2 2 Condensate 10C The mass flow rate of dry air is removal V V ACH (2 m 3 /change)(5 changes/min) m 1 car 11.55 kg/min a 3 v1 v1 0.8655 m The mass flow rates of vapor at the inlet and exit are m v1 1m a (0.01115)(11.55 kg/min) 0.1288 kg/min m v2 2 m a (0.00686)(11.55 kg/min) 0.07926 kg/min An energy balance on the control volume gives m a h1 Q out m a h2 m w hw2 where the the enthalpy of condensate water is hw2 h f@ 10C 42.02 kJ/kg (Table A - 4) and the rate of condensation of water vapor is m w m v1 m v2 0.1288 0.07926 0.0495 kg/min Substituting, m a h1 Q out m a h2 m w hw2 (11.55 kg/min)(55.60 kJ/kg) Q out (11.55 kg/min)(27.35 kJ/kg) (0.0495 kg/min)(42.02 kJ/kg) Q out 324.4 kJ/min 5.41 kW PROPRIETARY MATERIAL. © 2011 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. 14-50 AirH2O 0.050 Pressure = 101.3 [kPa] 0.045 0.040 35°C 0.035 0.8 0.030 30°C 0.6 0.025 0.020 25°C 0.4 Humidity Ratio 0.015 20°C 15°C 0.010 10°C 1 0.2 0.005 2 0.000 0 5 10 15 20 25 30 35 40 T [°C] Discussion We we could not show the process line between the states 1 and 2 because we do not know the process path. PROPRIETARY MATERIAL. © 2011 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. .

Copy Link

Recommended publications

The Potential and Challenges of Solar Boosted Heat Pumps for Domestic Hot Water Heating
Solar Calorimetry Laboratory The Potential and Challenges of Solar Boosted Heat Pumps for Domestic Hot Water Heating Stephen Harrison Ph.D., P. Eng., Solar Calorimetry Laboratory, Dept. of Mechanical and Materials Engineering, Queen’s University, Kingston, ON, Canada Solar Calorimetry Laboratory Background • As many groups try to improve energy efficiency in residences, hot water heating loads remain a significant energy demand. • Even in heating-dominated climates, energy use for hot water production represents ~ 20% of a building’s annual energy consumption. • Many jurisdictions are imposing, or considering regulations, specifying higher hot water heating efficiencies. – New EU requirements will effectively require the use of either heat pumps or solar heating systems for domestic hot water production – In the USA, for storage systems above (i.e., 208 L) capacity, similar regulations currently apply Canadian residential sector energy consumption (Source: CBEEDAC) Solar Calorimetry Laboratory Solar and HP water heaters • Both solar-thermal and air-source heat pumps can achieve efficiencies above 100% based on their primary energy consumption. • Both technologies are well developed, but have limitations in many climatic regions. • In particular, colder ambient temperatures lower the performance of these units making them less attractive than alternative, more conventional, water heating approaches. Solar Collector • Another drawback relates to the requirement to have an auxiliary heat source to supplement the solar or heat pump unit,
[Show full text]
Clean Coil Program
TM CLEAN COIL PROGRAM There are many good reasons to clean coils! And, here is what the Nu-Calgon Clean Coil & IAQ Assurance Program can do for you... Gain significant savings on energy costs. Maintain peak operating efficiency. Enhance the cooling system’s reliability and service life. Prevent costly breakdowns. Improve Indoor Air Quality (IAQ). Backed by Nu-Calgon, the leader in HVAC and Refrigeration maintenance chemicals for more than 60 years. www.nucalgon.com l www.coilcleaning.com l www.coilprotection.com NU-CALGON CLEAN COIL & IAQ ASSURANCE PROGRAM FOR AIR CONDITIONING, REFRIGERATION SYSTEMS Over the last 50 years, Nu-Calgon has developed products that have proven themselves in the successful cleaning and protection of air conditioning and refrigeration equipment. Now, these products have been further developed into a program that will keep this equipment operating efficiently and effectively, thereby cutting electric bills, increasing the equipment’s service life, and improving the comfort and Indoor Air Quality of the building or home. An air conditioning or refrigeration system has two “finned” coils, and typically they are constructed of copper tube and aluminum fins. The evaporator coil is the indoor coil, usually referred to as the “A” coil in residential systems. It could be described as “cold” as it provides indoor cooling by absorbing the heat as a fan passes the building air over it. The condenser coil or outdoor coil is the coil that is “warm” as it rejects the heat as a fan blows outdoor air across it. These coils are sized to match the Btu cooling load or requirement of the home or building, and they are engineered for maximum heat transfer .
[Show full text]
Indoor Air Quality Products Offering Healthy Home Solutions
Indoor Air Quality Products Offering Healthy Home Solutions Carrier clears the air for enhanced indoor comfort What You Can Expect From Carrier Innovation, efficiency, quality: Our Carrier® Healthy Home Solutions offers superior control over the quality of your indoor air and as a result, improved comfort. From air purification and filtration to humidity control, ventilation and more, these products represent the Carrier quality, environmental stewardship and lasting durability that have endured for more than a century. In 1902, that’s the year a humble but determined engineer solved one of mankind’s most elusive challenges – controlling indoor comfort. A leading engineer of his day, Dr. Willis Carrier would file more than 80 patents over the course of his career. His genius would enable incredible advancements in health care, manufacturing processes, food preservations, art and historical conservation, indoor comfort and much more. Carrier’s foresight changed the world forever and paved the way for over a century of once-impossible innovations. Designed with Your Comfort in Mind Carrier® Healthy Home Solutions represents years of design, development and testing with one goal in mind – maximizing your family’s comfort. Along the way, we have taken the lead with new technologies that deliver the superior performance you demand while staying ahead of industry trends and global initiatives. With innovations like Captures & Kills™ technology and superior humidity and airflow control, whatever your need, Carrier has a solution that’s perfectly tailored for you. 2 Ready to Clear the Air? The EPA has found that indoor levels of many air pollutants are often higher than outdoor levels.
[Show full text]
Cooling Towers and Condenser Water Systems Design and Operation
a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation • 2005 Cooling Towers and Condenser Water Systems Design and Operation an Engineers Newsletter Live telecast © 2005 American Standard Inc. Today’s Topics Fundamentals Chiller–tower interaction Cooling-tower terminology, operation Design conditions Cooling-tower control options System optimization © 2005 Standard Inc. American Answers to your questions © 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any 1 resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation • 2005 Today’s Presenters Dave Mick Lee Cline © 2005 Standard Inc. American Guckelberger Schwedler systems applications applications marketing engineer engineer engineer Cooling Towers and Condenser Water Systems Design and Operation Cooling tower fundamentals © 2005 American Standard Inc. © 2018 Trane a business of Ingersoll Rand. All rights reserved Trane, in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any 2 resulting system design. Design of the HVAC system is the prerogative and responsibility of the engineering professional. a Trane Engineers Newsletter Live Cooling Towers and Condenser Water Systems: Design and Operation • 2005 Refrigeration Cycle 2-stage compressor evaporator condenser economizer © 2005 Standard Inc. American expansion expansion device device Pressure–Enthalpy (p-h) Chart subcooled liquid liquid + vapor mix superheated pressure A B vapor 5 psia © 2005 Standard Inc. American 15.5 Btu/lb enthalpy 92.4 Btu/lb © 2018 Trane a business of Ingersoll Rand.
[Show full text]
Plate Heat Exchangers for Refrigeration Applications
Plate heat exchangers for refrigeration applications Technical reference manual A Technical Reference Manual for Plate Heat Exchangers in Refrigeration & Air conditioning Applications by Dr. Claes Stenhede/Alfa Laval AB Fifth edition, February 2nd, 2004. Alfa Laval AB II No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, recording, or otherwise, without the prior written permission of Alfa Laval AB. Permission is usually granted for a limited number of illustrations for non-commer- cial purposes provided proper acknowledgement of the original source is made. The information in this manual is furnished for information only. It is subject to change without notice and is not intended as a commitment by Alfa Laval, nor can Alfa Laval assume responsibility for errors and inaccuracies that might appear. This is especially valid for the various flow sheets and systems shown. These are intended purely as demonstrations of how plate heat exchangers can be used and installed and shall not be considered as examples of actual installations. Local pressure vessel codes, refrigeration codes, practice and the intended use and in- stallation of the plant affect the choice of components, safety system, materials, control systems, etc. Alfa Laval is not in the business of selling plants and cannot take any responsibility for plant designs. Copyright: Alfa Laval Lund AB, Sweden. This manual is written in Word 2000 and the illustrations are made in Designer 3.1. Word is a trademark of Microsoft Corporation and Designer of Micrografx Inc. Printed by Prinfo Paritas Kolding A/S, Kolding, Denmark ISBN 91-630-5853-7 III Content Foreword.
[Show full text]
Evaporator System Basics
Evaporator System Basics Today, more than ever, the cost of energy evaporator is always in liquid form and remains in represents a very significant part of the cost of liquid form even after the water is evaporated. operating a rendering plant. The recent rapid rise in energy costs has caused rendering plant The physical process of evaporation requires the operators to look for ways of improving the input of energy in the form of heat to convert a energy efficiency of plant operations. There are liquid into vapor. Since all evaporators use the many ways of accomplishing this goal, and one process of evaporation to remove water, every of the most effective ways is to use the energy evaporator requires a source of heat to operate. present the in waste vapor from the cooking The heat source for almost all evaporators is water operation. By using a waste heat evaporator, this vapor, either in the form of boiler steam or waste energy can be used to help evaporate the water in vapor from another process. the raw material prior to the cooker. The result is A second requirement for all evaporators is a a reduction in the amount of boiler steam required means to transfer heat energy from the heat source to cook the raw material and a corresponding into the evaporator liquid. Most evaporators increase in energy efficiency. use a tubular heater called a shell and tube heat The use of an evaporator is key in implementing exchanger for this purpose. In the heat exchanger this strategy. The following article outlines the shell, water vapor condenses on the outside of basics of evaporators and offers some guidance in the tubes thus giving up its heat energy, called choosing a suitable evaporator configuration.
[Show full text]
Design of a Low Capacity Evaporator of a Refrigeration Unit
Session 3666 Design of a Low capacity Evaporator of a Refrigeration Unit Alireza Mohammadzadeh Padnos School of Engineering Grand Valley State University Overview This project has been assigned to students in their first course in thermodynamics, in an attempt to satisfy the ABET requirement of enhancing the design contents of engineering courses. Although, refrigeration cycle is studied in thermodynamics classes and textbooks1, 2, 3 the details regarding the performance of each component of the cycle and its effect on the other parts of the refrigeration system is not considered. Moreover, little is said regarding the choice of working fluid and selection or design of individual components of the cycle. To help students understand how these components work together and how their inter-related performance affect the overall coefficient of performance of the cycle, they were required to choose an environmentally acceptable working fluid and to design the evaporator unit of a small capacity refrigeration unit (0.4 ton of refrigeration). Since students involved with this project do not have a fluid mechanics background, pressure drop in the system except for the case in the expansion valve is ignored. Due to the textbook1 used in their thermodynamics class students are familiar with the different mechanisms of heat transfer and are somewhat knowledgeable about convective heat transfer coefficient. This project not only teaches students how to manage and solve an open-ended problem, but also helps them to practice conservation of mass, first law and second law of thermodynamics. Students also learn more about conductive and convective modes of heat transfer by implementing the design steps for sizing the evaporator unit.
[Show full text]
Smimechanical
Mechanical SMI EVAPORATION Water Fracturing Technology SMI's proprietary fan design introduces water to the blade edges, fracturing water by the unique blade shape and high tip speed, then projecting the water into the air. Water fractur- ing evaporators can be land-based or floating on pontoons. 420F Evaporators The SMI 420 F Evaporator is our floating unit, designed for effective operation in small areas, especially sites containing large particles or highly corrosive water. High-speed fan blade rotation creates an optimum water droplet distribution for evaporation. The 420 F Evaporator is situated in the center of the reservoir, with the goal of containing un-evapo- rated liquids or solids within the permitted area. 420B Evaporators The SMI 420 B Evaporator is a land-based unit, designed to simply and reliably evaporate excess water in a variety of pond sizes, especially sites containing large particles or highly corrosive water. The 420 B is particularly suited for larger adjacent ponds with a dike in between where the boom can be rotated 180 degrees to spray water on either side depending upon wind. 420 Evaporators are designed for low buildup, high performance, easy maintenance, minimal clogging and extreme duty. 420 Evaporators are available in manual, stand- alone automated or premium automation with SMI's Smart H2O software. Annual evaporation rates up to 90% have been achieved with the 420, and averages are typi- cally between 25% and 60%. Evaporation rates depend on many factors, including ambient temperature, relative humidity, water make-up and wind conditions. Mechanical SMI EVAPORATION Water Atomizing Technology Air is compressed via a fan through a tapered barrel, propelling controlled-size water droplets created via nozzles.
[Show full text]
Fundamentals of Indoor Air Quality
Refrigeration Service Engineers Society 1666 Rand Road Des Plaines, Illinois 60016 FUNDAMENTALS OF INDOOR AIR QUALITY Frank Prah, CMS INTRODUCTION Indoor air quality in earlier times HVAC technicians are not medical doctors or indus- Anthropologists and forensic scientists know that trial hygienists. However, it is estimated that over primitive humans who lived in caves often suffered 80% of IAQ-related problems could be remedied by from poor IAQ. Smoke inhalation, dampness, and improving the design or maintenance program of generally unsanitary conditions, combined with a HVAC systems. The conclusion is obvious—in many poor diet, led to respiratory problems and arthritis. cases, a trained HVAC technician can improve the Smoke was also a problem in the Native American IAQ of a building or facility. tepee. The tepee actually had a ventilation system that worked reasonably well. However, the Indians An HVAC system serves as a distribution network for who lived in tepees had the same problem that we properly conditioned and filtered air in a building. The have today, especially during the winter. When we same system can serve as a path—and sometimes a increase ventilation, we pay an energy price. They source—for airborne pollutants. The contaminants also had to put up with cold drafts. Interestingly, some can and do affect the health and productivity of the winter camping sites were recently studied and com- building’s occupants. bustion air tunnels were found that led from outside the tepee to its center, where the fire was located. In the past, most of the instruction that a HVAC tech- Today, of course, heat wheels or heat tubes serve as nician received revolved around the mechanical, pip- heat exchangers and help reduce the energy penal- ing, and electrical aspects of installing and servicing ties associated with using outside air.
[Show full text]
EVAPCO for LIFE Full Spectrum Global Solutions
EVAPCO FOR LIFE Full Spectrum Global Solutions GLOBAL PRODUCT CATALOG Since 1976 Commercial HVAC | Industrial Refrigeration | An Employee-Owned Company Power Generation | Industrial Process EVAPCO for LIFE EVAPCO is more than a name. We are the global innovator in heat transfer solutions for the commercial HVAC, industrial refrigeration, power and industrial process markets. We pledge to make everyday life easier, more comfortable, more reliable and more sustainable for people everywhere. OUR COMMITMENT We never stop innovating. We set out to find groundbreaking solutions that transform the way the world works for the better. It’s why we have more than 28 patents worldwide in the last 10 years alone. We also guarantee performance and put every solution through rigorous research and testing to ensure maximum efficiency and reliability. PROTECTING THE ENVIRONMENT Innovation and environmental sustainability go hand-in-hand at EVAPCO. Our industrial heat transfer equipment not only conserves natural resources and helps reduce noise pollution, but also features recycled steel content in construction. Our stainless steel units are constructed of panels that contain up to 75% of recycled content and our galvanized units contain over 80%. From sound reduction to water conservation to chemical elimination, we are developing new technologies that deliver ultimate operating advantages to our clients while protecting the planet for every generation to come. 2 INSIDE Who We Are ...................... 2 Table of Contents . 3 Welcome .........................4 Full Spectrum Global Solutions ......5 Closed Circuit Coolers .............6 Cooling Towers ....................8 Condensers ......................10 Evaporators ...................... 12 Hygienic Air Handling Units ........ 14 Evapcold......................... 15 RVS–ASME Pressure Vessels ....... 16 Water Treatment Systems ...........17 EVAPCO Power .................
[Show full text]
Method 204F - Volatile Organic Compounds Content in Liquid Input Stream (Distillation Approach)
While we have taken steps to ensure the accuracy of this Internet version of the document, it is not the official version. Please refer to the official version in the FR publication, which appears on the Government Printing Office's eCFR website: (http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=515695243cf17599503c0e7a89f654a4&rgn=div9&view=text&node=40:2.0.1.1.2.23.11.5.30&idno=40) Method 204F - Volatile Organic Compounds Content in Liquid Input Stream (Distillation Approach) 1. Introduction 1.1 Applicability. This procedure is applicable for determining the input of volatile organic compounds (VOC). It is intended to be used as a segment in the development of liquid/gas protocols for determining VOC capture efficiency (CE) for surface coating and printing operations. 1.2 Principle. The amount of VOC introduced to the process (L) is the sum of the products of the weight (W) of each VOC containing liquid (ink, paint, solvent, etc.) used, and its VOC content (V), corrected for a response factor (RF). 1.3 Sampling Requirements. A CE test shall consist of at least three sampling runs. Each run shall cover at least one complete production cycle, but shall be at least 3 hours long. The sampling time for each run need not exceed 8 hours, even if the production cycle has not been completed. Alternative sampling times may be used with the approval of the Administrator. 2. Summary of Method A sample of each coating used is distilled to separate the VOC fraction. The distillate is used to prepare a known standard for analysis by a flame ionization analyzer (FIA), calibrated against propane, to determine its RF.
[Show full text]
Aprilaire.Dehumidifier.Frequently.Asked.Questions.Pdf
Dehumidification Frequently Asked Questions Dehumidification Basics Why do you want to keep indoor Rh between 30-60%? ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) recommends keeping the relative humidity in a home between 30-60% to limit the effects of many unwanted conditions and harmful household particles. In addition, the Journal of Allergy and Clinical Immunology recommends keeping indoor relative humidity below 51% in order to deter dust mites and boost overall comfort of the home. What areas of the country need whole-house dehumidification? Clearly, the weather and climate varies in different regions throughout the country. But regardless of locale, customers need a system designed to control humidity separate from cooling. Any region with a summer dew point average above 55° needs dehumidification separate from cooling. This would include cities such as Chicago – St. Louis – Baltimore – Atlanta – Orlando – all have dehumidification needs. How do you determine if a city has a need for dehumidification? We start by identifying parts of the country with the average summer dew point is above 55° because it represent areas where the humidity has the opportunity to rise above ideal levels ( a 55° represents 50% Rh at 75° F). Then we analyze the amount of time the outdoor temperature is between 55° and 75° F. This calculated time value shows how often there would be a need for dehumidification in a home but there would be no Air Conditioning load. Without air conditioning run time, there is no moisture removal from the home. What is the Sensible Heat Ratio (SHR) of Air Conditioning and how does it affect dehumidification in homes? The Sensible Heat Ratio (SHR) is the percentage of cooling in an Air Conditioning evaporator coil that is devoted to sensible vs.
[Show full text]