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. Get both Chvac and EnergyPro (which Chvac links to) and you'll have the most powerful, user-friendly commercial load calculation/energy analysis combo on the market.
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 rooms 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 room 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.
Camel Heat Load Calculation Software
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 Rooms per Project Rooms May Be Grouped Under 100 Air Handlers Rooms May Be Optionally Grouped Under VAV Boxes Allows 100 Walls, 100 Windows, and 100 Roofs per Room Allows Simultaneous Infiltration and Ventilation Allows Different Summer and Winter Air Rates Allows Different Indoor Conditions for each Room 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 room 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.
Five types of data are requested: general project data, outdoor design data, building material data, air handler data, and specific room 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 room data includes the room name, floor length and width, number of people, equipment watts, lighting watts, external shading data, and specific roof, wall, partition, floor and glass data.
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.
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 program (see more info in this paragraph). 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 to eQUEST 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).
Chvac now lets you import gbXML files from CAD drawing software such as AutoCAD MEP 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 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 a ready-to-open eQUEST project file from Chvac. Then you open that project in eQUEST, and enter any additional data you want to enter that is specific to 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).
HAP provides a graphical approach to creating building models for peak load and energy modeling projects. First import, scale, and orient architectural floor plan images. Then define multiple building levels (floors). Use the powerful new sketch-over to define the boundaries of spaces within the floor plans. The software will automatically calculate room dimensions and surface areas of floors, walls, ceilings, and roofs. Drag and drop window, door, and skylight rough openings. Configure sloped roofs, if necessary. From this data HAP extrudes the 2D floor plans into 3 dimensions, and renders the building for visualization and checking.
Heat load (or heating load) in relation to building physics refers to the amount of heating or cooling necessary to maintain the required temperature in a building or space within that building. This can be determined in relation either to the required heating or the required cooling. 2ff7e9595c
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