Reheat. By Michael F. Taras, Member ASHRAE The air-conditioning industry s focus on humidity issues has

Size: px
Start display at page:

Download "Reheat. By Michael F. Taras, Member ASHRAE The air-conditioning industry s focus on humidity issues has"

Transcription

1 The following article was published in ASHRAE Journal, December Copyright 2004 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. It is presented for educational purposes only. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. Reheat Which Concept Is Best By Michael F. Taras, Member ASHRAE The air-conditioning industry s focus on humidity issues has elevated the importance of dehumidifi cation. In addition, alternate refrigerants, such as R-410A, 1 may adversely impact system dehumidifi cation capability. This article evaluates various mechanical dehumidifi cation designs, including a two-phase refrigerant mixture concept, for air-conditioning and heat pump applications. Application requirements are the fi rst among many essential issues to be addressed when selecting the proper mechanical dehumidifi cation system using primary refrigerant. The system design strongly depends upon a range of indoor and outdoor environments, or stated differently, upon the relative signifi cance of sensible and latent load components over an array of operating conditions. Although a universal solution is desired, most systems are geared towards one end of the design spectrum or the other. The two-phase mixture concept may eliminate this controversy. A S H R A E J o u r n a l a s h r a e. o r g D e c e m b e r

2 Reheat Concepts Warm Liquid Refrigerant One of the most popular and efficient dehumidification designs for hot and humid environments that delivers both sensible and latent components of system capacity is the scheme using warm liquid refrigerant exiting the condenser coil (Figure 1). While the system is in dehumidification mode, the refrigerant exiting the condenser is rerouted to a reheat coil connected serially with the condenser and located behind the evaporator on the way to the indoor airstream supplied to the conditioned space. Thus, cooled and dehumidified air exiting the evaporator coil is reheated. During this heat transfer interaction, the liquid refrigerant circulating through the reheat coil is subcooled. As a result, the refrigerant enthalpy difference in the evaporator and evaporator capacity are increased. Therefore, the augmented subcooling is responsible for the evaporation temperature reduction and the system latent capacity boost. Since the system sensible capacity loss in the reheat coil is somewhat compensated for by the enhanced evaporator performance, the overall system cooling potential remains adequate. At the same time, a significant enhancement of the evaporator latent capacity is achieved. Since the system subcooling is only limited by the reheat coil size and air temperature leaving the evaporator (and not by usually much higher outdoor air temperature, as in other systems), the warm liquid refrigerant schematic becomes one of the most efficient techniques of increasing system dehumidification capability without compromising its cooling performance. One of the major concerns with multiple coil systems is refrigerant charge migration, which occurs when not all of the coils are always active. Refrigerant naturally migrates to the coldest region in the system, which may vary based on the operating mode and environmental conditions. This scheme is free of charge migration problems, since the reheat coil is always filled with liquid refrigerant, regardless of the operating mode. Hot Refrigerant Vapor Sequential Arrangement. Another design concept has been developed for the applications that do not require any sensible capacity delivered by the system. In such cases, the sensible portion of the evaporator capacity must be significantly reduced by reheating. The most popular approach uses compressor discharge gas rerouted to the reheat coil similarly placed in the indoor section behind the evaporator and connected sequentially with the main condenser. This concept allows reheating of the indoor airstream and considerable reduction of the system sensible capacity (Figure 2). As known, the sensible cooling capacity can be entirely eliminated only in a single design operating point, and at all other off-design conditions the system will deliver either some sensible cooling or heating to the conditioned space. Although the main condenser and reheat coil jointly act as a much larger condenser coil in the dehumidification mode, and the condensation temperature is noticeably reduced, the system subcooling is still limited by the outdoor air temperature. This constraint, in turn, limits the evaporator latent capacity, especially in cases when the main condenser coil is already large and its temperature approach is small in order to satisfy continually increasing system efficiency requirements. As a result, the system latent capacity cannot be appreciably increased over the conventional evaporator performance. As mentioned before, refrigerant migrates between the condenser and the reheat coil, depending on the operating mode and environmental conditions. In the dehumidification mode, the reheat coil primarily contains a two-phase refrigerant mixture, in comparison to the conventional cooling mode when it is not operational and filled with liquid refrigerant. On the other hand, the condenser coil holds predominantly a two-phase refrigerant, but during the dehumidification mode this refrigerant mixture is contained at lower pressure and density. As a result, the refrigerant charge rebalances, and alternating between the operational modes shouldn t cause any major charge migration issues. The reheat coil isolation methods are incorporated into some design configurations, but such flow control devices tend to leak over time and cannot be relied upon to permanently solve the charge migration problems. Also, the refrigerant bleed circuits are commonly used to assist in charge migration prevention. About the Author Michael F. Taras is a principal staff engineer and manager of technology at Carrier, Syracuse, N.Y. D e c e m b e r A S H R A E J o u r n a l 3 5

3 Characteristic Hot Gas Reheat Concept Two-Phase Mixture Reheat Concept Modes of Operation Two modes of operation: At least three modes of operation: conventional cooling Conventional cooling dehumidifi cation (hot gas) Dehumidifi cation (two-phase mixture) Cooling and enhanced dehumidifi cation (warm liquid) Variable Performance It is not feasible to vary system System performance at the design point performance at the design point can be controlled by a variable (modulation) or preset (pulsation) without altering the system components restriction in the condenser bypass line Size Smaller reheat coil Larger (10-20%) reheat coil Less uniform evaporator airfl ow More uniform (unaltered) evaporator airfl ow (altered airfl ow distribution relative to the conventional system); may cause fl ooding in some circuits Reliability Leakage through the three-way Leakage through the three-way and check valves and check valves Thermally stressed mixing joint (similar to the hot gas bypass not an issue) Flow change through the condenser (while switching between cooling and dehumidifi cation modes of operation) managed through proper condenser circuiting design Charge Migration Design is less stable due to Design is stable, minimal charge migration charge migration System operation is not altered System operation is more sensitive to charge migration Latent Capacity Maximization Latent performance of the reheat Latent performance of the dehumidifi cation cycle can signifi cantly cycle slightly exceeds latent capacity exceed latent capacity of the conventional system (indoor temperature of the conventional system limitation is less restrictive) (ambient temp. limitation is more restrictive) Operation at High Switching to the conventional Switching to the enhanced dehumidifi cation mode of operation at Ambient Temp. cooling mode of operation at high high ambient temperatures enhances dehumidifi cation ability of the ambient temp. reduces system (at ~75% of sensible capacity) dehumidifi cation ability of the system Switching to the conventional cooling mode provides dehumidifi cation capability equal to the hot gas reheat concept Ambient Temp. System performance degrades System performance improves at high ambient temperatures with the ambient temp. elevation: Sensible capacity is reduced at a lower rate (relative to the hot Sensible capacity ( ) gas reheat concept) Latent capacity ( ) Latent capacity is augmented Latent effi ciency ( ) Latent effi ciency is enhanced Head pressure control is activated Head pressure control is activated sooner to recover system sublater but is required for the conventional cooling at low ambient temp. cooling operation Indoor Humidity Identical performance to the two- Identical performance to the hot gas reheat concept phase mixture reheat concept Design is more sensitive to RH variations; head pressure control may need to be activated fl ow Design is less adaptable to head Design is more adaptable to head pressure control pressure control Head pressure control may need to be activated more frequently Indoor Dry-Bulb Temp. Design is insensitive to indoor Design is more sensitive to indoor temp. variations temp. variations Head pressure control may need to be activated at abnormally low temp. Table 1: Comparison of hot gas reheat concept with two-phase mixture reheat concept. Parallel Configuration. An alternate and relatively popular approach uses compressor discharge gas in a similar fashion, with the exception that the reheat coil is positioned in a parallel arrangement with the main condenser and the latter is taken out of the circuit in the dehumidification mode of operation (Figure 3). Although the performance of such a design is not thoroughly investigated in this article, several features of the system operation are discussed below. First, the reheat coil in the dehumidification mode solely performs the condensation function but is much smaller than the combined condenser/reheat coil in the previous arrangements. Consequently, the system performance and life-cycle cost of the equipment may be affected. Additionally, when the reheat cycle is activated, the parallel hot gas configuration will always deliver heat (at least for a single-circuit system), since the heat rejected into the conditioned space (comprised of the condenser heat flux and indoor fan power) exceeds the evaporator sensible capacity. As a result, the controls constantly alternate between the cooling and dehumidification modes of operation in order to maintain the design point of the time-averaged neutral (zero) sensible capacity. Therefore, additional instability, reliability and control issues may be undesirably introduced into the system design and operation. Another drawback of this type of system is that the airflow cannot be used as a head pressure control parameter, since the reheat coil and the evaporator are coupled by the indoor airstream. Also, since the main condenser and reheat coil are functionally separated, the system design is more susceptible to refrigerant charge migration. As was mentioned previously, the flow control 3 6 A S H R A E J o u r n a l a s h r a e. o r g D e c e m b e r

4 Three-way Three-way Check Check Figure 1 (left): Warm liquid refrigerant cycle. Figure 2 (right): Sequential hot gas refrigerant cycle. devices such as conventional solenoid, three-way and liquid line check valves may be introduced to isolate the reheat circuit, they leak over time, usually causing the refrigerant charge to migrate to the condenser in the dehumidification mode. To protect against the charge imbalance and Advertisement formerly in this space. migration, a small bleed line with a solenoid valve and/or a hot gas bypass circuit often are integrated into the design. Two-Phase Refrigerant Mixture A novel approach using a mixture of hot compressor discharge gas and warm liquid exiting the condenser has been recently developed (Figure 4). In this schematic, the refrigerant flow at the compressor exit splits into two streams, with one of them completing the conventional path through the condenser and the other rerouted around the condenser coil. Both refrigerant streams rejoin at the condenser exit, forming a two-phase mixture. As in the warm liquid dehumidification concept, the refrigerant subsequently enters the reheat coil, but in an entirely different two-phase state, where it is further condensed and then subcooled. As before, during this heat transfer interaction the airstream exiting the evaporator is reheated. An amount of flow bypassing the condenser (all other parameters being identical) determines the vapor content (quality) in the refrigerant at the mixing point, defines the reheat coil capacity and consequently establishes the evaporator performance (based on the amount of subcooling gained). If the bypass refrigerant flow is increased, the mixing point shifts into the higher vapor quality region inside the two-phase dome, which in turn enhances the reheat coil capacity (Figure 5). Since the system subcooling is concurrently reduced, the evaporator performance diminishes accordingly. Obviously, the bypass flow reduction causes just the opposite effect. As a result, the designs for multiple market requirements in terms of evaporator latent and system sensible capacity are feasible, by means of modulating or pulsating the condenser bypass flow and without changing any of the system components. It becomes quite obvious that if the conventional refrigerant path through the condenser is closed, the proposed system turns into the parallel hot gas design. On the other hand, if the bypass around the condenser is closed the system develops into the warm liquid design. Apparently, some flexibility could be achieved for all the previous designs if the fixed-position valves are substituted with the regulating or pulsating flow control devices. Unfortunately, all these schemes offer significantly lower agility in system design and may encounter more complex control and reliability issues. On the contrary, the two-phase refrigerant system offers at least three distinct modes of operation to satisfy a wide range of environmental conditions and load demands. The system provides adequate operation for conventional cooling applications, for hot and humid environments and for low sensible load cases, by alternating between these operating modes. Finally, although implementation of the D e c e m b e r A S H R A E J o u r n a l 3 7

5 Three-way Three-way 2a Bypass 3a 2 1 Check Check Expansion Device Figure 3 (left): Parallel hot gas refrigerant cycle. Figure 4 (right): Two-phase mixture refrigerant cycle. considered design may require a slightly larger reheat coil than in the sequential hot gas approach, the original evaporator airflow distribution won t be compromised, preventing a potential flooding problem in some of the evaporator circuits. Off-Design Conditions It is essential to analyze each design concept at off-design conditions in terms of system reaction and sensitivity to various environmental parameters and operational characteristics. Issues such as performance degradation, potential system malfunctioning, reliability and required changes in the control logic must be evaluated carefully. The following parameters are considered the most critical for system operation and have been thoroughly examined: ambient temperature, indoor humidity, outdoor airflow, indoor airflow and indoor temperature. In particular, the two-phase mixture design is compared to one of the most popular hot gas reheat concepts. Ambient Temperature All air-conditioning systems must operate at various ambient conditions and should be able to sustain the desired performance in the dehumidification mode of operation as well. A significant advantage of the two-phase mixture concept is that its performance improves with the ambient temperature. Conversely, the performance of the hot gas schemes diminishes at the conditions when dehumidifcation is needed most. At relatively high ambient temperatures both sensible and latent components of the system capacity are required to satisfy increased cooling and dehumidification demands. In such ambient conditions, the hot gas design would switch to the conventional cooling mode. The two-phase mixture system, however, has the option to either naturally transition to the warm liquid mode (by completely closing the condenser bypass valve) or to operate in the conventional cooling mode. In the latter case, both systems perform identically. Although for the hot gas design the sensible system capacity is significantly enhanced in the conventional cooling mode of operation, its latent performance drops, in comparison to the dehumidification cycle. Conversely, for the two-phase mixture system, its latent performance is improved when the transition to the warm liquid concept occurs while the sensible capacity reaches reasonably high levels (~75%). Thus, it becomes obvious that the two-phase mixture system inherently has a higher degree of flexibility in design and in satisfying various latent and sensible load demands. Indoor Humidity It is not uncommon for dehumidification systems to operate in environments with varying indoor humidity levels. Therefore, the system should be able to adequately respond to the humidity changes by removing sufficient amount of moisture in order to keep the conditioned space within the comfort zone or recommended specification. Both the hot gas and two-phase mixture designs react similarly to the variations in the indoor humidity and exhibit identical performance trends, providing an equal ability to remove moisture from the indoor airstream. The most noticeable enhancement in the latent performance, in comparison to the conventional system, is achieved at the lower end of the relative humidity spectrum, as a result of the improved reheat coil operation at lower evaporation temperatures. flow Outdoor (condenser) airflow affects many of the system operational parameters and should be given special attention in the evaluation of the dehumidification system performance. Although the majority of air-conditioning systems are not yet configured for variable-speed operation, the trend of achieving higher efficiencies and reducing the lifetime cost of the equipment is becoming one of the most critical concerns in the industry. In addition, many applications use various methods of outdoor airflow adjustment to achieve the required head pressure control in order to avoid system malfunction or failure. Also, operating the system in dirty environments may vary condenser airside impedance, causing a change in the fan operating point 3 8 A S H R A E J o u r n a l a s h r a e. o r g D e c e m b e r

6 P Three-way Bypass Solenoid Three-way Solenoid h Figure 5 (left): P-h diagram for two-phase mixture refrigerant cycle. Figure 6 (right): Hybrid reheat schematic. and the amount of delivered airflow. Thus, it becomes important to analyze the effect of the outdoor airflow on dehumidification system performance. Another substantial advantage of the two-phase mixture design is that it is more adaptable to the head pressure control by means of the condenser airflow adjustment through continuous modulation or fan cycling. On the contrary, the hot gas schematics are either insensitive to the previously mentioned control methods or such control techniques are not feasible due to the specific system configurations, such as in the case of the parallel hot gas system. The rates of change in essential performance characteristics for both dehumidification concepts are almost identical. The most improvement in the dehumidification capability, relative to the conventional system, can be achieved at the lower end of the airflow spectrum, since the reheat coil plays a more significant role in latent performance enhancement at higher condensation temperatures. Conditioned Space Temperature and Airflow Because the conditioned space temperature is highly application dependent, it is practical to evaluate the dehumidification system performance at various indoor dry-bulb temperatures. Similarly, indoor airflow can vary for a number of reasons. For instance, variable air volume (VAV) and variable volume temperature (VVT) systems are found in multiple applications in the industry. In addition, plugged filters or customized ductwork may cause a shift in the indoor fan operating point, even for the preset airflow systems. Therefore, it is essential to evaluate the influence that the amount of supplied air and the temperature of the conditioned space have on the dehumidification system performance. As expected, both systems operate in a similar fashion, exhibit identical trends, reveal no malfunction problems and have no detrimental effect on the end customers. Design Comparison A selected dehumidification system design should be tailored towards the requirements of a particular application in terms of the cooling and heating needs and the moisture removal criterion. Several of the previously mentioned schematics have been investigated, and it was found that the twophase mixture scheme provides the most adequate coverage for a wide spectrum of potential applications. This approach offers superior flexibility in satisfying a wide range of latent and sensible capacity demands. It also provides an essential advantage of minimizing or even reversing undesirable tendencies in system performance deviation for a majority of off-design conditions. The system functionality or component reliability are not compromised if adequately addressed through the appropriate control logic (e.g., activation of the head pressure control) and careful component design (reheat coil size selection, condenser circuiting, etc.). The essential results and conclusions of the analysis are summarized in Table 1, which compares the two-phase mixture design with one of the most popular hot gas reheat concepts. To further improve system flexibility, all the fixed-position two-way and three-way valves can be replaced with controllable devices to regulate the amount of the refrigerant flowing through every branch of the dehumidification cycle. Additionally, all of the designs can be used in the multicircuit systems where each circuit is controlled independently. Several hybrid concepts have been developed recently as well in order to satisfy an even wider range of cooling, heating and dehumidification requirements. These systems can operate in several of the dehumidification modes discussed previously by opening and closing the appropriate flow control devices to reroute the refrigerant through a particular branch of the cycle. Figure 6 shows one such schematic where the two solenoid valves and two shutoff valves (replacing typical check valves) manage an appropriate refrigerant flow path in response to external sensible and latent load demands. Since the complexity in design and control logic for these systems increases proportionally, any subsystem of the hybrid design can be implemented and executed independently. References 1. Lemmon, E.W., M.O. McLinden, M.L. Huber NIST Reference Fluid Thermodynamic and Transport Properties REFPROP 7.0. National Institute of Standards and Technology. Physical and Chemical Properties Division.

APPLICATION GUIDE. Comparison of Latent Cooling Performance of Various HVAC systems in a Classroom Application

APPLICATION GUIDE. Comparison of Latent Cooling Performance of Various HVAC systems in a Classroom Application APPLICATION GUIDE Comparison of Latent Cooling Performance of Various HVAC systems in a Classroom Application Section Comparison of Latent Cooling Performance of Introduction Most commercial HVAC systems

More information

COMMERCIAL HVAC CHILLER EQUIPMENT. Air-Cooled Chillers

COMMERCIAL HVAC CHILLER EQUIPMENT. Air-Cooled Chillers COMMERCIAL HVAC CHILLER EQUIPMENT Air-Cooled Chillers Technical Development Programs (TDP) are modules of technical training on HVAC theory, system design, equipment selection and application topics. They

More information

Dr. Michael K. West, PE 1 Dr. Richard S. Combes, PE 2 Advantek Consulting / Melbourne, Florida

Dr. Michael K. West, PE 1 Dr. Richard S. Combes, PE 2 Advantek Consulting / Melbourne, Florida Optimizing 100% Outside Air Systems with Heat Pipes Dr. Michael K. West, PE 1 Dr. Richard S. Combes, PE 2 Advantek Consulting / Melbourne, Florida Introduction To meet increasingly rigorous building codes

More information

Why and How we Use Capacity Control

Why and How we Use Capacity Control Why and How we Use Capacity Control On refrigeration and air conditioning applications where the load may vary over a wide range, due to lighting, occupancy, product loading, ambient weather variations,

More information

Low GWP Replacements for R404A in Commercial Refrigeration Applications

Low GWP Replacements for R404A in Commercial Refrigeration Applications Low GWP Replacements for R404A in Commercial Refrigeration Applications Samuel YANA MOTTA, Mark SPATZ Honeywell International, 20 Peabody Street, Buffalo, NY 14210, Samuel.YanaMotta@honeywell.com Abstract

More information

A Comparison of an R22 and an R410A Air Conditioner Operating at High Ambient Temperatures

A Comparison of an R22 and an R410A Air Conditioner Operating at High Ambient Temperatures R2-1 A Comparison of an R22 and an R410A Air Conditioner Operating at High Ambient Temperatures W. Vance Payne and Piotr A. Domanski National Institute of Standards and Technology Building Environment

More information

Characteristics of Evaporators

Characteristics of Evaporators Characteristics of Evaporators Roger D. Holder, CM, MSME 10-28-2003 Heat or Energy In this paper, we will discuss the characteristics of an evaporator coil. The variance of the operational condenses of

More information

Heat Recovery In Retail Refrigeration

Heat Recovery In Retail Refrigeration This article was published in ASHRAE Journal, February 2010. Copyright 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Posted at www.ashrae.org. This article may not

More information

SECTION 5 COMMERCIAL REFRIGERATION UNIT 22 CONDENSERS

SECTION 5 COMMERCIAL REFRIGERATION UNIT 22 CONDENSERS SECTION 5 COMMERCIAL REFRIGERATION UNIT 22 CONDENSERS UNIT OBJECTIVES After studying this unit, the reader should be able to explain the purpose of the condenser in a refrigeration system. describe differences

More information

Failure code manual. content

Failure code manual. content Failure code manual content 一 wall split AC series 2 二 floor standing AC series. 4 三 portable AC series.. 5 四 dehumidifer 6 五 DC inverter single split series...7 六 DC inverter multi-split series 10 1 一

More information

Introduction. Motor Types

Introduction. Motor Types QwikSEER+ Theory of Operation and Retrofit Potential Mainstream Engineering Corporation Rockledge, FL 32955 http://www.qwik.com/products/qwikseer/index.jsp Prepared by Robert P. Scaringe and R. Paul Roth

More information

How Ground/Water Source Heat Pumps Work

How Ground/Water Source Heat Pumps Work How Ground/Water Source s Work Steve Kavanaugh, Professor Emeritus of Mechanical Engineering, University of Alabama Ground Source s (a.k.a. Geothermal s) are becoming more common as the costs of energy

More information

Rittal White Paper 508: Economized Data Center Cooling Defining Methods & Implementation Practices By: Daniel Kennedy

Rittal White Paper 508: Economized Data Center Cooling Defining Methods & Implementation Practices By: Daniel Kennedy Rittal White Paper 508: Economized Data Center Cooling Defining Methods & Implementation Practices By: Daniel Kennedy Executive Summary Data center owners and operators are in constant pursuit of methods

More information

Pool Dehumidification Basics

Pool Dehumidification Basics Copyright 2009 Wescor. All rights reserved. Permission granted to reproduce for personal and educational use only. When energy costs were low, many pool owners considered only first cost when choosing

More information

newsletter engineers energy-saving strategies for Water-Source Heat Pump Systems volume 36 2 providing insights for today s hvac system designer

newsletter engineers energy-saving strategies for Water-Source Heat Pump Systems volume 36 2 providing insights for today s hvac system designer engineers volume 36 2 newsletter providing insights for today s hvac system designer energy-saving strategies for Water-Source Heat Pump Systems from the editor... Water-source heat pump (WSHP) systems

More information

MULTIZONE APPLICATION OF SOLUTION UNITS

MULTIZONE APPLICATION OF SOLUTION UNITS MULTIZONE APPLICATION OF SOLUTION UNITS APPLICATION GUIDE Supersedes: 102.20-AG12 (206) Form: 102.20-AG12 (307) GENERAL Multi-zone heating and air conditioning units offer design and application advantages

More information

NEBB STANDARDS SECTION-8 AIR SYSTEM TAB PROCEDURES

NEBB STANDARDS SECTION-8 AIR SYSTEM TAB PROCEDURES NEBB STANDARDS SECTION-8 AIR SYSTEM TAB PROCEDURES 8.1 INTRODUCTION Testing, adjusting, and balancing of HVAC systems can best be accomplished by following a series of systematic procedures. The NEBB TAB

More information

Defining Quality. Building Comfort. Precision. Air Conditioning

Defining Quality. Building Comfort. Precision. Air Conditioning Defining Quality. Building Comfort. Precision Air Conditioning Today s technology rooms require precise, stable environments in order for sensitive electronics to operate optimally. Standard comfort air

More information

APPLICATION GUIDE. Moisture Management in Waterborne Climate Systems

APPLICATION GUIDE. Moisture Management in Waterborne Climate Systems APPLICATION GUIDE Moisture Management in Waterborne Climate Systems Contents Introduction 3 WBCS Concept 3 Condensation 4 Moisture Sources in the Space 4 Impact of a High Moisture Load 5 Designing to Manage

More information

Theoretical Study on Separate Sensible and Latent Cooling Air-Conditioning System

Theoretical Study on Separate Sensible and Latent Cooling Air-Conditioning System Purdue University Purdue e-pubs International Refrigeration and Air Conditioning Conference School of Mechanical Engineering 2008 Theoretical Study on Separate Sensible and Latent Cooling Air-Conditioning

More information

Lesson 36 Selection Of Air Conditioning Systems

Lesson 36 Selection Of Air Conditioning Systems Lesson 36 Selection Of Air Conditioning Systems Version 1 ME, IIT Kharagpur 1 The specific objectives of this chapter are to: 1. Introduction to thermal distribution systems and their functions (Section

More information

Venice Library Humidity Study. for Williams Building Diagnostics, LLC 305 15 th Street West Bradenton, FL 34205. Report April 13, 2015

Venice Library Humidity Study. for Williams Building Diagnostics, LLC 305 15 th Street West Bradenton, FL 34205. Report April 13, 2015 for Williams Building Diagnostics, LLC 305 15 th Street West Bradenton, FL 34205 Report April 13, 2015 Moses & Associates, Inc. 2209 NW 40 th Terrace, Suite A Gainesville, FL 32605 FL License EB-0003097

More information

AIR CONDITIONING TECHNOLOGY

AIR CONDITIONING TECHNOLOGY AIR CONDITIONING TECHNOLOGY PART 9 Water Cooled Condensers & Cooling Towers IN LAST month s article we looked at how Air Cooled Condensers are used to transfer the total heat of rejection from the air

More information

Controlling Wrap-Around Heat Pipes for Systems with Strict Space Humidity Requirements. By Michael O. Davis, PE, November 2015

Controlling Wrap-Around Heat Pipes for Systems with Strict Space Humidity Requirements. By Michael O. Davis, PE, November 2015 Controlling Wrap-Around Heat Pipes for Systems with Strict Space Humidity Requirements By Michael O. Davis, PE, November 2015 Advised by Heat Pipe Technology Background: HVAC systems are often designed

More information

Data Center Design Guide featuring Water-Side Economizer Solutions. with Dynamic Economizer Cooling

Data Center Design Guide featuring Water-Side Economizer Solutions. with Dynamic Economizer Cooling Data Center Design Guide featuring Water-Side Economizer Solutions with Dynamic Economizer Cooling Presenter: Jason Koo, P.Eng Sr. Field Applications Engineer STULZ Air Technology Systems jkoo@stulz ats.com

More information

How To Understand Evaporator

How To Understand Evaporator SECTION 5 COMMERCIAL REFRIGERATION UNIT 21 EVAPORATORS AND THE REFRIGERATION SYSTEM UNIT OBJECTIVES After studying this unit, the reader should be able to Define high-, medium-, and low-temperature refrigeration.

More information

Heat Recovery Dehumidification (HRD) system. Designed for municipal swimming pools

Heat Recovery Dehumidification (HRD) system. Designed for municipal swimming pools Heat Recovery Dehumidification (HRD) system Designed for municipal swimming pools A dehumidification and ventilation system with dynamic heat pump heat recovery to swimming pool water and air ENVIRONMENTAL

More information

newsletter Let s take a high-level look at airside economizing: what it is, what it requires, and how it s done. How does economizer cooling work?

newsletter Let s take a high-level look at airside economizing: what it is, what it requires, and how it s done. How does economizer cooling work? engineers volume 35 2 newsletter providing insights for today s hvac system designer keeping cool with outdoor air Airside Economizers from the editor For the denizens of commercial buildings, comfort

More information

R22. K Control. Indoor Unit. Nomenclature. Compatibility PL H 3 G K H B. Unit style Heat Pump Horse Power

R22. K Control. Indoor Unit. Nomenclature. Compatibility PL H 3 G K H B. Unit style Heat Pump Horse Power R22. K Control. Indoor Unit. Nomenclature. PL H 3 G K H B Compatibility Unit style Heat Pump Horse Power Control Boost Heaters R22. K Control. Outdoor Unit. Nomenclature. PU H 3 Y K A Compatibility Outdoor

More information

PHCC Educational Foundation Contractor Library Engineering Continuing Education

PHCC Educational Foundation Contractor Library Engineering Continuing Education PHCC Educational Foundation Contractor Library Engineering Continuing Education Engineering-Specific Courses This list includes engineering-specific courses only. Descriptions for all approved courses

More information

Innovent LASER Packaged Fresh Air Conditioning Units

Innovent LASER Packaged Fresh Air Conditioning Units LASER Latent And Sensible Energy Reduction Latent And Sensible Energy Reduction For Outside Air Innovent LASER Packaged Fresh Air Conditioning Units Innovent LASER units provide both sensible and latent

More information

HVAC Systems: Overview

HVAC Systems: Overview HVAC Systems: Overview Michael J. Brandemuehl, Ph.D, P.E. University of Colorado Boulder, CO, USA Overview System Description Secondary HVAC Systems Air distribution Room diffusers and air terminals Duct

More information

HEAT RECOVERY OPTIONS FOR DRYERS AND OXIDIZERS

HEAT RECOVERY OPTIONS FOR DRYERS AND OXIDIZERS HEAT RECOVERY OPTIONS FOR DRYERS AND OXIDIZERS William K. Scullion, Application Engineering Leader, MEGTEC Systems, De Pere, WI Introduction Competitive pressures continuously motivate us to examine our

More information

THERMO KING TRUCK & TRAILER UNIT ALARM CODES THIS DOCUMENT SHOWS ALL CURRENT ALARM CODES FOR THERMO KING TRUCK AND TRAILER UNITS.

THERMO KING TRUCK & TRAILER UNIT ALARM CODES THIS DOCUMENT SHOWS ALL CURRENT ALARM CODES FOR THERMO KING TRUCK AND TRAILER UNITS. THERMO KING TRUCK & TRAILER UNIT ALARM CODES THIS DOCUMENT SHOWS ALL CURRENT ALARM CODES FOR THERMO KING TRUCK AND TRAILER UNITS. NOT ALL CODES ARE POSSIBLE ON ANY INDIVIDUAL UNIT. IF THE ALARM APPLIES

More information

COMMERCIAL HVAC EQUIPMENT. Condensers and Cooling Towers

COMMERCIAL HVAC EQUIPMENT. Condensers and Cooling Towers COMMERCIAL HVAC EQUIPMENT Condensers and Cooling Towers Technical Development Programs (TDP) are modules of technical training on HVAC theory, system design, equipment selection and application topics.

More information

Akton Psychrometric Chart Tutorial and Examples

Akton Psychrometric Chart Tutorial and Examples Akton Psychrometric Chart Tutorial and Examples December 1999 Akton Associates Inc. 3600 Clayton Road, Suite D Concord, California 94521 (925) 688-0333 http://www.aktonassoc.com Copyright 1999 Akton Associates

More information

Energy Recovery Ventilation Equipment

Energy Recovery Ventilation Equipment AHRI Standard 1060 (I-P) 2013 Standard for Performance Rating of Airto-Air Exchangers for Energy Recovery Ventilation Equipment IMPORTANT SAFETY DISCLAIMER AHRI does not set safety standards and does not

More information

Sustainable Preservation Practices for Managing Storage Environments Webinar: April 3, 2013

Sustainable Preservation Practices for Managing Storage Environments Webinar: April 3, 2013 The Fundamentals of HVAC: What Shapes the Storage Environment Sustainable Preservation Practices for Managing Storage Environments Webinar: April 3, 2013 Introduction Presenter Jeremy Linden, Preservation

More information

Element D Services Heating, Ventilating, and Air Conditioning

Element D Services Heating, Ventilating, and Air Conditioning PART 1 - GENERAL 1.01 OVERVIEW A. This section supplements Design Guideline Element D3041 on air handling distribution with specific criteria for projects involving design of a Data Center spaces B. Refer

More information

Presentation Outline. Common Terms / Concepts HVAC Building Blocks. Links. Plant Level Building Blocks. Air Distribution Building Blocks

Presentation Outline. Common Terms / Concepts HVAC Building Blocks. Links. Plant Level Building Blocks. Air Distribution Building Blocks Presentation Outline Common Terms / Concepts HVAC Building Blocks Plant Level Building Blocks Description / Application Data Green opportunities Selection Criteria Air Distribution Building Blocks same

More information

STEAM HEATING SYSTEM TROUBLESHOOTING GUIDE

STEAM HEATING SYSTEM TROUBLESHOOTING GUIDE Page 1 of 9 PURPOSE Steam is the most commonly used heating medium for maintaining process temperatures. Compared to other heating media, steam contains a significant amount of heat energy, and this heat

More information

Any Service Technician Can Fix It A Good Service Technician Can Figure Out What s Wrong With It.

Any Service Technician Can Fix It A Good Service Technician Can Figure Out What s Wrong With It. I Dave s Statement If the thermostat calls for cooling, and the furnace fan is running properly, and the coil airflow is adequate, and the condenser fan is running properly, and the condenser airflow is

More information

Glossary of Heating, Ventilation and Air Conditioning Terms

Glossary of Heating, Ventilation and Air Conditioning Terms Glossary of Heating, Ventilation and Air Conditioning Terms Air Change: Unlike re-circulated air, this is the total air required to completely replace the air in a room or building. Air Conditioner: Equipment

More information

By Tom Brooke PE, CEM

By Tom Brooke PE, CEM Air conditioning applications can be broadly categorized as either standard or critical. The former, often called comfort cooling, traditionally just controlled to maintain a zone setpoint dry bulb temperature

More information

Application Engineering

Application Engineering Application Engineering February 2012 Digital Capacity Control for Copeland Scroll Refrigeration Compressors INDEX Page 1. Introduction... 1 2. Theory of Operation... 1 3. Nomenclature... 1 4. Digital

More information

Todd M. Rossi, Ph.D. President

Todd M. Rossi, Ph.D. President Residential Air Conditioning Fault Detection and Diagnostics (FDD) and Protocols to Support Efficient Operation DOE - Building America Program Residential Buildings Integration Meeting - July 20-22, 2010

More information

Single Zone LCD Thermostat Operating Instructions

Single Zone LCD Thermostat Operating Instructions Fan Cool Furnace *Heat Pump or Heat Strip On/Off F Single Zone LCD Thermostat Operating Instructions MODEL 3313192.XXX Cool/Furnace 3313193.XXX Cool/Furnace/Heat Pump 3313194.XXX Cool/Furnace/Heat Strip

More information

INSTALLATION INSTRUCTIONS HOT GAS BYPASS SYSTEM DESIGN MANUAL

INSTALLATION INSTRUCTIONS HOT GAS BYPASS SYSTEM DESIGN MANUAL INSTALLATION INSTRUCTIONS HOT GAS BYPASS SYSTEM DESIGN MANUAL MODELS: WA/WL44H WA/WLH WA/WL70*H NOTE: Electrical data presented in this manual supersedes any other data f the above listed models. Bard

More information

HEAT RECOVERY FROM CHILLED WATER SYSTEMS. Applications for Heat Reclaim Chillers

HEAT RECOVERY FROM CHILLED WATER SYSTEMS. Applications for Heat Reclaim Chillers HEAT RECOVERY FROM CHILLED WATER SYSTEMS Applications for Heat Reclaim Chillers April 2008 TABLE OF CONTENTS INTRODUCTION... 3 WASTE HEAT SOURCES... 3,4 Capturing Sufficient Heat for Useful Purposes...

More information

Commercial refrigeration has been in the environmental. Refrigerant. as a. Basics Considerations PART 1:

Commercial refrigeration has been in the environmental. Refrigerant. as a. Basics Considerations PART 1: PART 1: CO 2 Commercial refrigeration has been in the environmental spotlight for more than a decade, especially as leakage studies have revealed the true effects of hydrofluorocarbon (HFC) emissions.

More information

ICE THERMAL STORAGE IN AIR CONDITIONING APPLICATION FUNDAMENTALS

ICE THERMAL STORAGE IN AIR CONDITIONING APPLICATION FUNDAMENTALS ICE THERMAL STORAGE IN AIR CONDITIONING APPLICATION FUNDAMENTALS By: T. S. Wan Date: April 19, 1994 (1st draft 3/7/86) Copyright 1994 by T. S. Wan (All rights reserved) ABSTRACT: The technology of energy

More information

Analysis of data centre cooling energy efficiency

Analysis of data centre cooling energy efficiency Analysis of data centre cooling energy efficiency An analysis of the distribution of energy overheads in the data centre and the relationship between economiser hours and chiller efficiency Liam Newcombe

More information

Tech Byte 27: Small Computer Room and IT Closet Cooling

Tech Byte 27: Small Computer Room and IT Closet Cooling Questions Answered in This Paper Sensible cooling capacity is the measuring stick for IT cooling capacity needs. What is the sensible cooling capacity of the comfort split system in comparison to the precision

More information

ROOFTOP - HEAT PUMP UNIT. This document applies when installing into an air handler or as part of an air handling system.

ROOFTOP - HEAT PUMP UNIT. This document applies when installing into an air handler or as part of an air handling system. ROOFTOP - HEAT PUMP UNIT Technical data Applies to Model YNRA R410A This document applies when installing into an air handler or as part of an air handling system. CONTENTS 1. General description... 2

More information

SPECIAL ISSUE: NATIONAL SCIENCE FOUNDATION WORKSHOP

SPECIAL ISSUE: NATIONAL SCIENCE FOUNDATION WORKSHOP research journal 2013 / VOL 05.01 www.perkinswill.com SPECIAL ISSUE: NATIONAL SCIENCE FOUNDATION WORKSHOP ARCHITECTURE AND ENGINEERING OF SUSTAINABLE BUILDINGS Current Trends in Low-Energy HVAC Design

More information

Glossary of HVAC Terms

Glossary of HVAC Terms Glossary of HVAC Terms Heating, Ventilation and Air Conditioning (HVAC) is a major sub- discipline of mechanical engineering. The goal of HVAC design is to balance indoor environmental comfort with other

More information

CURBING THE COST OF DATA CENTER COOLING. Charles B. Kensky, PE, LEED AP BD+C, CEA Executive Vice President Bala Consulting Engineers

CURBING THE COST OF DATA CENTER COOLING. Charles B. Kensky, PE, LEED AP BD+C, CEA Executive Vice President Bala Consulting Engineers CURBING THE COST OF DATA CENTER COOLING Charles B. Kensky, PE, LEED AP BD+C, CEA Executive Vice President Bala Consulting Engineers OVERVIEW Compare Cooling Strategies in Free- Standing and In-Building

More information

Evaluation Of Hybrid Air- Cooled Flash/Binary Power Cycle

Evaluation Of Hybrid Air- Cooled Flash/Binary Power Cycle INL/CON-05-00740 PREPRINT Evaluation Of Hybrid Air- Cooled Flash/Binary Power Cycle Geothermal Resources Council Annual Meeting Greg Mines October 2005 This is a preprint of a paper intended for publication

More information

The Different Types of Air Conditioning Equipment for IT Environments

The Different Types of Air Conditioning Equipment for IT Environments The Different Types of Air Conditioning Equipment for IT Environments By Tony Evans White Paper #59 Executive Summary Cooling equipment for an IT environment can be implemented in 10 basic configurations.

More information

Instruction manual for Firstline FCS12000CH

Instruction manual for Firstline FCS12000CH Instruction manual for Firstline FCS12000CH Contents Introduction... 2 Safety Awareness... 3 Safety Awareness... 4 Name of Parts... 5 Name of Parts... 6 Remote Controller Preparation... 7 Operation of

More information

imagine SOLAR AIR CONDITIONING MADE EASY

imagine SOLAR AIR CONDITIONING MADE EASY imagine SOLAR AIR CONDITIONING MADE EASY WHY SOLAR COOLING? Imagine...being able to fit a solar air conditioning system to your building that would result in dramatic reductions in electricity consumption

More information

Engineering White Paper UTILIZING ECONOMIZERS EFFECTIVELY IN THE DATA CENTER

Engineering White Paper UTILIZING ECONOMIZERS EFFECTIVELY IN THE DATA CENTER Engineering White Paper UTILIZING ECONOMIZERS EFFECTIVELY IN THE DATA CENTER SUMMARY A proper balance of temperature and humidity control is essential for efficient data center operation, and integral

More information

Environmental and Safety Impacts of HFC Emission Reduction Options for Air Conditioning and Heat Pump Systems

Environmental and Safety Impacts of HFC Emission Reduction Options for Air Conditioning and Heat Pump Systems Environmental and Safety Impacts of HFC Emission Reduction Options for Air Conditioning and Heat Pump Systems William M. Corcoran, George Rusch, Mark W. Spatz, and Tim Vink AlliedSignal, Inc. ABSTRACT

More information

Energy savings in commercial refrigeration. Low pressure control

Energy savings in commercial refrigeration. Low pressure control Energy savings in commercial refrigeration equipment : Low pressure control August 2011/White paper by Christophe Borlein AFF and l IIF-IIR member Make the most of your energy Summary Executive summary

More information

saving energy in comfort Factsheet Recair Enthalpy

saving energy in comfort Factsheet Recair Enthalpy saving energy in comfort Factsheet Recair Enthalpy Introduction Enthalpy Exchanger The enthalpy exchanger is able to transfer both sensible heat and latent heat (moisture) from the cooled to the heated

More information

Causes of High Relative Humidity Inside Air Conditioned Buildings. Roger G.Morse AIA, Paul Haas CSP, CIH Morse Zehnter Associates

Causes of High Relative Humidity Inside Air Conditioned Buildings. Roger G.Morse AIA, Paul Haas CSP, CIH Morse Zehnter Associates Causes of High Relative Humidity Inside Air Conditioned Buildings Roger G.Morse AIA, Paul Haas CSP, CIH Morse Zehnter Associates S. FLORIDA AVE. AMBIENT 91 F db / 78 F wb 16,000 HOURS ANNUALLY THAT wb

More information

Example Retrocommissioning Measure: Opening Throttled Discharge Valves

Example Retrocommissioning Measure: Opening Throttled Discharge Valves Opening Throttled Discharge Valves This 21-story building, constructed in 1997, is located in Oregon and contains 589,000 gross square feet of mostly office occupancy. The HVAC system includes six large

More information

85 F 80 F 50% 75 F 70 F 73.0/61.8 45 F 10% Figure 1

85 F 80 F 50% 75 F 70 F 73.0/61.8 45 F 10% Figure 1 Feb. 07 INTRODUCTION: Wrap around heat pipes are air-to-air heat exchangers that are installed in the airstream upstream and downstream of a cooling coil to deliberately reduce the Sensible Heat Ratio

More information

WHITE PAPER #: CLIMATEMASTER KNOWLEDGE SERIES: HEAT PUMP DESIGN FOR 100% OUTSIDE AIR SYSTEMS THE SMART SOLUTION FOR ENERGY EFFICIENCY

WHITE PAPER #: CLIMATEMASTER KNOWLEDGE SERIES: HEAT PUMP DESIGN FOR 100% OUTSIDE AIR SYSTEMS THE SMART SOLUTION FOR ENERGY EFFICIENCY WHTE PPE #: 5 THE SMT SUTN F ENEGY EFFENY MTEMSTE KNWEDGE SEES: HET PUMP DESGN F 100% UTSDE SYSTEMS WTE-SUE HET PUMP SYSTEMS Table of ontents: ntroduction... 2 Background on oops... 2 Heat Pump Principles...

More information

Skills Canada National Competition Instructions and Competition Details 38 Refrigeration and Air Conditioning / Post - Secondary May 27-30, 2015 -

Skills Canada National Competition Instructions and Competition Details 38 Refrigeration and Air Conditioning / Post - Secondary May 27-30, 2015 - Skills Canada National Competition Instructions and Competition Details / Post - Secondary May 27-30, 2015 - Saskatoon 1. Test Project Details This project is designed to test the range of skills used

More information

Engineering Recommendation on: Accumulators Revised 6-17-99 Issued January 10, 1979 Page 1 of 7

Engineering Recommendation on: Accumulators Revised 6-17-99 Issued January 10, 1979 Page 1 of 7 Issued January 10, 1979 Page 1 of 7 Accumulators have long been recognized by the industry as an effective means of maintaining good system balance by storing excess refrigerant as the condenser or evaporator

More information

Indoor coil is too warm in cooling mode or too cold in heating mode. Reversing valve or coil thermistor is faulty

Indoor coil is too warm in cooling mode or too cold in heating mode. Reversing valve or coil thermistor is faulty Codes Room Air Conditioner range: Indoor unit alarm s If timer lamp flashes for 1 second on, 1 second off, this indicates pre heating on the coil during heating mode and is not an error. If timer lamp

More information

Creating Efficient HVAC Systems

Creating Efficient HVAC Systems Creating Efficient HVAC Systems Heating and Cooling Fundamentals for Commercial Buildings Heating, ventilating, and air conditioning (HVAC) systems account for nearly half of the energy used in a typical

More information

Applying Pressure Independent Control Valves in H.V.A.C. Systems. A Presentation to: Orange Empire ASHRAE Santa Ana Nov. 17, 2009

Applying Pressure Independent Control Valves in H.V.A.C. Systems. A Presentation to: Orange Empire ASHRAE Santa Ana Nov. 17, 2009 Applying Pressure Independent Control Valves in H.V.A.C. Systems A Presentation to: Orange Empire ASHRAE Santa Ana Nov. 17, 2009 1 Introduction I know, as building design consultants, so much of your effort

More information

SAMPLE CHAPTERS UNESCO EOLSS

SAMPLE CHAPTERS UNESCO EOLSS STEAM TURBINE OPERATIONAL ASPECTS R.A. Chaplin Department of Chemical Engineering, University of New Brunswick, Canada Keywords: Steam Turbines, Operation, Supersaturation, Moisture, Back Pressure, Governing

More information

HVAC Technologies for Building Energy Efficiency Improvements 2013 National Symposium on Market Transformation. Richard Lord Carrier Fellow

HVAC Technologies for Building Energy Efficiency Improvements 2013 National Symposium on Market Transformation. Richard Lord Carrier Fellow HVAC Technologies for Building Energy Efficiency Improvements 2013 National Symposium on Market Transformation Richard Lord Carrier Fellow HVAC Industry Challenges and Issues Ozone Deletion Global Warming

More information

Improving Data Center Energy Efficiency Through Environmental Optimization

Improving Data Center Energy Efficiency Through Environmental Optimization Improving Data Center Energy Efficiency Through Environmental Optimization How Fine-Tuning Humidity, Airflows, and Temperature Dramatically Cuts Cooling Costs William Seeber Stephen Seeber Mid Atlantic

More information

HOT & COLD. Basic Thermodynamics and Large Building Heating and Cooling

HOT & COLD. Basic Thermodynamics and Large Building Heating and Cooling HOT & COLD Basic Thermodynamics and Large Building Heating and Cooling What is Thermodynamics? It s the study of energy conversion using heat and other forms of energy based on temperature, volume, and

More information

Technical Support Bulletin Nr. 20 Special AC Functions

Technical Support Bulletin Nr. 20 Special AC Functions Technical Support Bulletin Nr. 20 Special AC Functions Summary! Introduction! Hot Start Control! Adaptive Control! Defrost Start Temperature Compensation Control! Anti-Sticking Control! Water Free Cooling

More information

Air Conditioning 101. STN Presentation AC101

Air Conditioning 101. STN Presentation AC101 Air Conditioning 101 What is Refrigeration? Refrigeration is Cooling by the Removal of Heat Heat is Measured In BTU s A BTU is a British Thermal Unit It is the Amount of Heat to Raise One Pound of Water,

More information

To provide good indoor air quality

To provide good indoor air quality Conditioning Ventilation Air for Improved Performance and Air Quality The practice of using a mixing chamber for mixing outdoor and return in a single system should be replaced by a technique with two

More information

Automobile Air Conditioning Primer

Automobile Air Conditioning Primer Automobile Air Conditioning Primer An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like Freon, to provide cooling. The mechanics of the

More information

New Trends in the Field of Automobile Air Conditioning

New Trends in the Field of Automobile Air Conditioning New Trends in the Field of Automobile Air Conditioning E. Janotkova and M. Pavelek Department of Thermomechanics and Environmental Engineering Brno University of Technology, 61669 Brno, Czech Republic

More information

Evaporative Cooling for Residential and Light-Commercial

Evaporative Cooling for Residential and Light-Commercial EMERGING TECHNOLOGIES This article was published in ASHRAE Journal, October 2011. Copyright 2011 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Posted at www.ashrae.org.

More information

Troubleshooting an Air Conditioning system. R D Holder Eng. Roger D Holder MSME

Troubleshooting an Air Conditioning system. R D Holder Eng. Roger D Holder MSME Troubleshooting an Air Conditioning system R D Holder Eng. Roger D Holder MSME Troubleshooting of an air conditioning system is a step by step procedure. I have found that a 4 step procedure is the best

More information

The Development of a Frost-Less Heat Pump

The Development of a Frost-Less Heat Pump The Development of a Frost-Less Heat Pump V. C. Mei, R. E. Domitrovic, and F. C. Chen, Oak Ridge National Laboratory J. K. Kilpatrick, Tennessee Valley Authority ABSTRACT There are two major concerns associated

More information

Total Heat Versus Sensible Heat Evaporator Selection Methods & Application

Total Heat Versus Sensible Heat Evaporator Selection Methods & Application Total Heat Versus Sensible Heat Evaporator Selection Methods & Application Scope The purpose of this paper is to provide specifying engineers, purchasers and users of evaporators in industrial refrigeration

More information

16. Heat Pipes in Electronics Cooling (2)

16. Heat Pipes in Electronics Cooling (2) 16. Heat Pipes in Electronics Cooling (2) 16.1 Pulsating Heat Pipes 16.1.1Introduction Conventional heat pipe technology has been successfully applied in the last thirty years for the thermal management

More information

Yijun Gao, Wei Wu, Zongwei Han, Xianting Li *

Yijun Gao, Wei Wu, Zongwei Han, Xianting Li * Study on the performance of air conditioning system combining heat pipe and vapor compression based on ground source energy-bus for commercial buildings in north China Yijun Gao, Wei Wu, Zongwei Han, Xianting

More information

Building Performance With District Cooling

Building Performance With District Cooling Reprinting this proof for distribution or posting on web sites is not permitted. Authors may request permission to reprint or post on their web site once the fi nal version has been published. A reprint

More information

GEOTHERMAL HEATING AND COOLING INTRODUCTION

GEOTHERMAL HEATING AND COOLING INTRODUCTION GEOTHERMAL HEATING AND COOLING INTRODUCTION Geothermal Heating and Cooling Systems provide space conditioning -- heating, cooling, and humidity control. They may also provide water heating -- either to

More information

Programmable Thermostat MODEL 3312026.XXX With Dehumidify 3312024.XXX With Out Dehumidify

Programmable Thermostat MODEL 3312026.XXX With Dehumidify 3312024.XXX With Out Dehumidify Comfort Control Center 2 Thermostat Operating Instructions Programmable Thermostat MODEL 3312026.XXX With Dehumidify 3312024.XXX With Out Dehumidify TABLE OF CONTENTS About your new thermostat Features...2

More information

Refrigeration Basics 101. By: Eric Nelson

Refrigeration Basics 101. By: Eric Nelson Refrigeration Basics 101 By: Eric Nelson Basics Refrigeration is the removal of heat from a material or space, so that it s temperature is lower than that of it s surroundings. When refrigerant absorbs

More information

Nordic Heat Pump Product Guide

Nordic Heat Pump Product Guide Nordic Heat Pump Product Guide About Maritime Geothermal Maritime Geothermal is a privately owned, Canadian based manufacturer of geothermal heat pumps. We began manufacturing the Nordic line of heat pumps

More information

Research on the Air Conditioning Water Heater System

Research on the Air Conditioning Water Heater System Purdue University Purdue e-pubs International Refrigeration and Air Conditioning Conference School of Mechanical Engineering 28 Research on the Air Conditioning Water Heater System Fei Liu Gree Electric

More information

Federal Wage System Job Grading Standards for Air Conditioning Equipment Operating, 5415. Table of Contents

Federal Wage System Job Grading Standards for Air Conditioning Equipment Operating, 5415. Table of Contents Federal Wage System Job Grading Standards for Air Conditioning Equipment Operating, 5415 Table of Contents WORK COVERED... 2 WORK NOT COVERED...2 TITLES... 2 GRADE LEVELS... 2 HELPER AND INTERMEDIATE JOBS...

More information

High Pressure Ammonia Systems New Opportunities

High Pressure Ammonia Systems New Opportunities Purdue University Purdue e-pubs International Refrigeration and Air Conditioning Conference School of Mechanical Engineering 2010 High Pressure Ammonia Systems New Opportunities Andy Pearson Star Refrigeration

More information

Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal

Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal Technical Bulletin By Bruce I. Nelson, P.E., President, Colmac Coil Manufacturing, Inc. Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal SUMMARY Refrigeration air coolers (evaporators)

More information

LIQUID DESICCANT AIR CONDITIONING Saves energy, Controls humidity, Cleans air. Trevor Wende Vice President, Marketing Advantix Systems, Inc.

LIQUID DESICCANT AIR CONDITIONING Saves energy, Controls humidity, Cleans air. Trevor Wende Vice President, Marketing Advantix Systems, Inc. LIQUID DESICCANT AIR CONDITIONING Saves energy, Controls humidity, Cleans air Trevor Wende Vice President, Marketing Advantix Systems, Inc. 0 Humidity: The Hidden Cost Driver Conventional A/C process Start

More information

Hospital Application Guide. Cost-effective climate control for hospitals

Hospital Application Guide. Cost-effective climate control for hospitals Hospital Application Guide Cost-effective climate control for hospitals Munters is the world leader in dehumidification Munters is the largest manufacturer of dehumidifiers in the world. Since developing

More information