Chvac - Commercial HVAC Loads

Commercial Load Calculations Done Right
Chvac has been an industry leader in commercial load calculation software since 1979. Try Elite Software's flagship program today and see why so many professional engineers are choosing Chvac.

Features
Calculates Peak Heating & Cooling Loads
Determines Building Tonnage and Room CFM Requirements, and Runout Duct Sizes
Uses either the RTS or CLTD calculation method
Computes CFM Air Quantities With Psychrometrics
Calculates from Manually Entered Data or Directly from Floor Plans Created with Drawing Board (sold separately)
Imports and exports gbXML files
New! Allows Different Indoor Conditions for each Zone
Links with Energy Audit Program
Links with PsyChart program. The PsyChart program can import Chvac system data directly into its Air Handler Model window.
Links with HVAC Solution program.
Transfers data to the eQUEST and PowerDOE Energy Analysis Programs (more on using eQUEST with Chvac).
Allows 30 Walls, 30 Windows, and 12 Roofs per Zone
Automates Compliance with ASHRAE Standard 62
Calculates in both Metric and English Units
Converts any project from English to Metric units and vice-versa
Allows Simultaneous Infiltration and Ventilation
Calculates Runout and Main Trunk Duct Sizes
Selects Equipment from ARI/GAMA Databases
Allows Virtually Unlimited Number of Zones
Zones May be Optionally Grouped Under VAV Boxes
Prints Numerous Color Pie Charts and Bar Graphs
Creates Spreadsheet Output File

Overview
Chvac quickly and accurately calculates the maximum heating and cooling loads for commercial buildings. The cooling loads can be calculated with either the CLTD method or the new RTS (Radiant Time Series) method. The program allows an unlimited number of zones which can be grouped into as many as 100 air handling systems. Chvac automatically looks up all cooling load and correction factors necessary for computing loads. In addition, it can look up outdoor design weather data for over 2000 cities located around the world. There is also provision for editing the weather data as well as adding data for other cities. Comprehensive reports list the general project data, detailed zone loads, air handler summary loads, outside air loads, total building loads, building envelope analysis, tonnage requirements, CFM air quantities, chilled water flow rates (if applicable), and complete psychrometric data with entering and leaving coil conditions. Other outstanding features include ASHRAE Standard 62 analysis, automatic building rotation, 360 degree wall orientations, tilted glass, exterior shading, internal operating load profiles, variable indoor design temperatures, people diversity, pretreated outside air, seasonal infiltration and ventilation rates, reheat loads, duct gains and losses, and return air plenums.

Five Versions Available
There are five versions of the Chvac program; 2 zone capacity ($295), 10 zone capacity ($395), 50 zone capacity ($595), 100 zone capacity ($995), and unlimited capacity ($1495). Keep in mind that a zone is a single space or room, and that zones can be grouped into air handling systems which in turn make up the building. Zones can optionally be grouped under vav boxes as well. This allows Chvac to compute diversified peak loads at four levels in one run of the program: zone, vav box, air system, and total building. The maximum number of air handling systems allowed for any version is the number of zones allowed or 100, whichever is the lesser. Each Chvac version is exactly the same with the exception of the zone capacity and price. However, there is a generous upgrade policy. If at any time you decide to obtain a version of Chvac with greater capacity than the original one you obtained, all that is required is to pay the difference in price between the two versions.

Advanced Features
Chvac contains many, many advanced features. Here are just a few of its capabilities.

Calculates Peak Heating and Cooling Loads
Calculates Both Heating & Cooling CFM Requirements
Calculates Runout and Main Trunk Duct Sizes
Automates Compliance with ASHRAE Standard 62
Provides Overall Building Envelope Report
Creates Spreadsheet File with Calculated Results
Performs Complete Psychrometric Analysis
Prints Bar Graphs and Exploded Pie Charts
Exterior Shading Handles Overhangs, Fins, & Glass Tilt
Uses Exact ASHRAE RTS or CLTD Procedures
Built-in Design Weather Data for Hundreds of Cities
Analyzes Up to 12 Months Per Calculation
Calculates 24 Hours per Design Day
Allows Unlimited Number of Zones per Project
Zones May Be Grouped Under 100 Air Handlers
Zones May Be Optionally Grouped Under VAV Boxes
Allows 100 Walls, 100 Windows, and 100 Roofs per Zone
Allows Simultaneous Infiltration and Ventilation
Allows Different Summer and Winter Air Rates
Allows Different Indoor Conditions for each Zone
Allows 20 Master Roof Types, 20 Master Wall Types, 20 Master Partition Types, and 50 Master Glass Types
Provides a User-Defined Library of Custom Materials
Provides a List of your Favorite Materials
Allows Up to 10 Internal Operating Load Profiles
Allows Full 360 Degree Wall and Glass Orientations
Allows Glass to be titled from 0 to 180 degrees
Allows for Roof and Wall Color Effects
Provision for Both VAV and Constant Volume Systems
Proper Handling of Return Air Plenum Loads
Accounts for People Diversity in Total Building Load
Computes Supply Fan Horsepower and Heat Gains
Accounts for Both Draw-thru and Blow-thru Fans
Calculates Reheat Requirements if Necessary
Computes Supply and Return Duct Gains and Losses
Allows Direct Specification of Supply CFM Quantities
Allows Specification of Minimum Supply Air Quantities
Allows Heating Only, Cooling Only, or Both
Excess Supply Air Can be Handled as Reheat, Reserve Capacity, or by Adjusting the Leaving Coil Conditions
Leaving Coil Conditions Can be Specified with a Desired Dry Bulb Temperature or a Relative Humidity
Calculates Chilled and Hot Water Coil Flow Rates
Allows for Pretreated Outside Air
Calculates benefits of Heat Recovery Ventilators (HRV) for heating and cooling
Allows Heating and Cooling Safety Factors
Lighting & Equipment Watts along with No. of People can be Entered Directly or on a Per Square Foot Basis
Selects Equipment from the ARI/GAMA Databases
Creates Custom Sales Proposals
Creates Spreadsheet Output File

Calculation Method
Chvac performs cooling calculations using either the CLTD method or the new RTS (Radiant Time Series) method. The RTS method is described in the latest edition of the ASHRAE Handbook of Fundamentals, while the CLTD method is from earlier editions of the Handbook. The RTS method is especially accurate because it calculates the delayed effect of radiant heat gains during each of the past 24 hours in determining the current cooling load. That means, for example, that the program gives proper consideration to the effect of an external shading device that shades a window in the morning in a zone that peaks in the afternoon. The CLTD method, on the other hand, uses exact table values from the Handbook where possible, which means that you can verify the results by hand. You can actually switch back and forth between RTS and CLTD for any project. All you have to do to switch between the two methods is to enter equivalent Master Data definitions for roofs, walls and glass and then change the Cooling Calculation Method input to the other method.

Program Input
Chvac is very easy to use and includes a specific "dropdown" help window for virtually every input, including a list of choices where appropriate. The program performs extensive checks on the data you enter and alerts you to any problems that it finds, such as a wall having too much window area, or a leaving coil temperature for an air handler outside of the expected range.

Five types of data are requested: general project data, outdoor design data, building material data, air handler data, and specific zone data. The general project data includes the project and client name, designer, building opening and closing hours, internal operating load schedules, and any desired safety factors. The outdoor design data includes the summer and winter outdoor design conditions (automatically looked up for you if a city reference is given) and the desired ventilation and infiltration rates. The building material data includes the definition of master building material types for roofs, walls, partitions, glass sections, and exterior shading. A user defined material library is available for saving the data on common material types. The air handler data includes the fan and terminal type, the desired heating and cooling supply air temperatures and data for duct heat gains and losses. The zone data includes the zone name, floor length and width, number of people, equipment watts, lighting watts, external shading data, and specific roof, wall, partition, floor and glass data.

Program Output
Chvac provides several different types of reports which can be selectively previewed on screen or printed. The reports are: General Project Data, Air Handler Input Data, Zone Input Data, Detailed Project Zone Loads, Air System Zone Summary, Total Building, Air System, and Zone Load Profiles, Air System Total Load Summary, Air System Psychrometric Analysis, Psychrometric Chart, Overall Building Envelope Report, Pie Charts, Bar Graphs, and the Total Building Load Summary. Virtually all calculated data can be exported to a comma delimited text file that you can then import into your favorite spreadsheet program such as Excel.

Chvac and HVAC Solution Link
The Chvac load calc program calculates a great deal of the data needed to define a system in the HVAC Solution schematic diagramming program. Traditionally, this data has simply been transferred using a manual entry process. Now, there is an automated process whereby HVAC Solution can import all the relevant Chvac data system by system into the HVAC Solution software such that HVAC schematic diagrams are automatically generated. See a video demo of this process here and view more details on HVAC Solution here.

Links to Other Programs
Chvac not only calculates peak heating and cooling loads, it also aids in selecting HVAC equipment and analyzing building operating costs. Project data from Chvac can be exported to Elite Software's Energy Audit program as well as to the eQUEST (see more info in the next paragraph) and PowerDOE programs (in the future, we plan to also provide a link to the Energy Plus program). Export to Energy Audit when you want to analyze residential and light commercial projects, essentially any application which uses unitary HVAC equipment. Export eQUEST or PowerDOE when you want to analyze large commercial projects that require precise modeling of variable loads, equipment, operating schedules, and control schemes. For just selecting unitary HVAC equipment, use the built-in Find HVAC Equipment feature of reading equipment performance databases published by the American Refrigeration Institute (ARI) and the Gas Appliance Manufacturers Association (GAMA).

Import and Export of gbXML Files
Chvac now lets you import gbXML files from CAD drawing software such as AutoCAD MEP 2008 and many other programs. We give you extensive control over the import process, including the ability to select which spaces, walls and windows to include in the import (see screenshot below). If you are familiar with the data that CAD programs typically write to gbXML files, you know that material definitions are usually incomplete for purposes of load calculation, since they do not usually include data such as wall U-values or roof ASHRAE numbers. So on the import dialog we let you select the default definitions for each kind of master material in the project.

Using eQUEST with Chvac for LEED Certification
Using the free eQUEST program with Chvac gives you a complete load calculation and energy analysis package. First, you enter your project in Chvac and let it determine your peak loads. Then, you export an INP file from Chvac and import it into eQUEST. Then eQUEST will let you perform a detailed energy analysis. The eQUEST program can also be used to perform the calculations required for the energy portion of LEED certification, as described in an article in the September 2007 ASHRAE Journal (page 58 and following).

Drawing Board
A functional demo of Drawing Board is built into this version of Chvac. The built-in demo version of Drawing Board allows you to draw and save floor plans of unlimited size, but HVAC calculations can only be made for two zones of the floor plan.

Update Information
Chvac users with earlier versions can update to version 7 for a substantial discount off the full purchase price. If you have Chvac version 6.01 through 6.04 it is VERY IMPORTANT that you first download and install the final revision of 6.04 before installing version 7. The final version of 6.04 includes changes that prevent you from mistakenly opening a project file in the wrong version of the program.

New Features in Version 7
The following new features were added to version 7 that were not in version 6.

RTS Calculation Method: You can now select to use either the CLTD method or the new Radiant Time Series (RTS) method for calculating cooling loads. The RTS method is found in the latest ASHRAE Handbook of Fundamentals and is very accurate because it calculates the delayed effect of radiant heat gains during each of the past 24 hours on the current cooling load. You can easily switch back and forth between the two methods simply by entering equivalent master roof, wall and glass data on the Master Data window for both methods.


Easier and Better Glass Definitions: Now you can enter the width and height dimensions for each window or skylight rather than having to enter them for the master glass and then figure out the correct quantity to enter on the Zone Data window. The Room Construction value of Light, Medium or Heavy required for each glass in the CLTD method is now automatically assigned based on the selection you make for the entire zone in the new Zone Type input.


Individual Ground Reflectance Values: You can enter a different ground reflectance for each component rather than having only one value for the whole project, which makes the results more accurate because different exposures around a building are likely to have different ground reflectances. Because the RTS method requires this input for roofs and walls, each roof and wall now has a Ground Reflectance input, which makes it so each skylight and window is automatically assigned a ground reflectance value that is appropriate for its exposure.


Glass Number of Occurrences: You only have to enter data once for a window or skylight that occurs multiple times in the same wall or roof.


Floor Slab Coefficient for Each Zone: You can now enter the floor slab coefficient for each zone rather than having to use the same value for the whole project.


Easier to Use Zone Data Window: The Zone Data window has been redesigned to make it easier to enter all the data. You can change the number of visible roofs, walls and glass by clicking the plus and minus buttons next to each group's scrollbar. Pressing Enter when on the last visible row of a component now makes the components scroll down by one so you can enter another item of the same type. If the Type input of a component is set to zero, pressing Enter moves the cursor to the next group of inputs. All the important data is now on two tabs instead of three.


More Roofs, Walls and Glass per Zone: We've more than doubled the allowed number of roofs, walls and glass you can enter for a zone.


Zone Notes: You can save as many notes about a zone as you want in the new "Notes About This Zone" input on the Zone Data window.


Easier Weather Data Selection: Both the Weather Database and the Indoor/Outdoor Design windows now let you select a city from a single dropdown list that shows all cities in the database.


Easier Weather Database Editing: It is now much easier to edit and add cities in the redesigned Weather Database window.

Screen shots

Comprehensive Air Handler Data


Runout and Main Trunk Duct Sizing


Built-in Custom and Favorite Material Lists


Easy Zone Data Entry


All Types of Exterior Shading


Import and Export of gbXML Files


Drawing Board Window
Chvac includes a Drawing Board window, which operates at the demo level until you purchase a separate license for Drawing Board. The Drawing Board window enables you to enter your room data by simply drawing the floor plan on the screen. Below is a screen shot showing a floor plan created from within Chvac.

Screen shots Comprehensive Air Handler Data Runout and Main Trunk Duct Sizing Built-in Custom and Favorite Material Lists Easy Zone Data Entry All Types of Exterior Shading Import and Export of gbXML Files Drawing Board Window

谢谢楼主推荐的软件,不过这个软件有没有中文版的？

目前没有中文版的
我安装了，还在研究中:lol

到哪里去下啊？好像收费的啊

我还在试用。
网址自己根据名字可以找到的

试用版啊？看起来还不普及嘛