Engineering & Knowledge

Fundamentals & Engineering

Design Procedures for Heating-Only Systems: An 8-Step Methodology

Designing effective heating-only HVAC systems requires a methodical approach that ensures adequate capacity while avoiding oversizing. The following 8-step procedure provides a comprehensive framework for designing these systems, focusing on peak heating loads to determine appropriate equipment sizing.

Space and Zone Airflow Sizing Calculations in HVAC Systems

Following our previous discussion on the systematic 9-step procedure for designing cooling and heating systems, it’s essential to understand the technical aspects of airflow sizing

Design Procedures for Cooling-Only Systems: Detailed Airflow Calculation Methodology

this technical supplement provides detailed insights into the critical airflow calculation methods essential for Step 3: Calculate Required Zone and Space Supply Airflow Rates. Understanding these calculation approaches enables engineers to select the most appropriate sizing method for specific project requirements.

Design Procedures for Heating-Only Systems: Airflow Calculation Methods and Technical Considerations

Proper airflow calculations are essential for system performance, ensuring thermal comfort while optimizing energy efficiency. Understanding the mathematical foundation behind these calculations enables engineers to make informed decisions when selecting the most appropriate sizing method for specific project requirements.

Refrigeration Expansion Valve Sizing and Selection Process

The proper selection and sizing of refrigeration expansion valves is a systematic process requiring careful consideration of multiple parameters. Selecting the right expansion valve involves understanding system requirements, calculating correct capacities, and accounting for operating conditions such as subcooling and pressure drop.

Refrigeration Evaporator Sizing and Selection

Evaporator sizing and selection represent critical elements in refrigeration system design. The process requires a methodical approach that considers not only the cooling load but also system integration, refrigerant properties, application requirements, and energy efficiency goals.

Lighting Rules Of Thumb (HVAC)

Using lighting rules of thumb for final design of HVAC and lighting.

Infiltration Rules Of Thumb

The infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (CFM) or liters per second (LPS). The air exchange rate, (I), is the number of interior volume air changes that occur per hour, and has units of 1/h.

Cooling Load Calculation Procedure

Cooling Load Calculation Procedure for HVAC Design. From Obtain Building Characteristics to Outdoor Design Weather Conditions and indoor design temperature to be maintained in each space.

The Geometry Behind Solar Energy Calculations

Solar Geometric Angles are all critical to the calculation of solar energy on any given surface at some orientation. To calculate the energy balance across any time scale with respect to the incident solar radiation, you must know the geometric relationships that define the spherical realities of planetary motion relative to the sun for specific tilted surfaces on the planet.

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Standards & Compliance

HVAC Ventilation Design: Exhaust Air Ventilation By Rate and ACH

Complete guide to HVAC exhaust air ventilation design using ASHRAE, CIBSE, and Carrier standards covering rate calculations, ACH requirements, and specialized applications for effective contaminant removal and energy efficiency.

HVAC Ventilation Design: Outdoor Air Ventilation By Rate and ACH

Complete guide to HVAC outdoor air ventilation design using ASHRAE, CIBSE, and Carrier standards covering rate calculations, ACH requirements, and building-specific applications for optimal indoor air quality.

HVAC Ventilation Design: Indoor Air Quality and Air Contaminants

Complete guide to HVAC indoor air quality and air contaminant management using ASHRAE, CIBSE standards covering contaminant identification, control strategies, and advanced treatment technologies for healthy indoor environments.

HVAC Ventilation Design: Air Intake Minimum Separation Distance

Complete guide to HVAC air intake minimum separation distances using ASHRAE 62.1 standards covering contamination source requirements, measurement methods, and compliance strategies for optimal outdoor air quality protection.

HVAC Ventilation Design: Air Classifications

Complete guide to HVAC air classifications using ASHRAE 62.1 and CIBSE standards covering air quality categories, contamination levels, filtration requirements, and ventilation strategies for optimal indoor environmental control.

HVAC Ventilation Design: General Schematic and Equations

Complete guide to HVAC ventilation design using ASHRAE 62.1 standards covering calculation procedures, system schematics, and modern ventilation strategies for optimal indoor air quality and energy efficiency.

HVAC Load Estimation: Fouling Factor

Complete guide to fouling factors in HVAC load estimation using Carrier water conditioning standards for accurate heat transfer equipment sizing and comprehensive water quality management strategies.

HVAC Load Estimation: Diversity Factor

Complete guide to diversity factors in HVAC load estimation using CIBSE and Carrier standards for accurate system sizing that reflects realistic building operation patterns and prevents equipment oversizing.

HVAC Load Estimation: Indoor Design Conditions and System Requirements by Building Type

Complete guide to indoor design conditions for HVAC load estimation covering temperature, humidity, air quality, and specialized requirements for residential, commercial, industrial, healthcare, and specialty building applications using ASHRAE, CIBSE, and Carrier standards.

HVAC Load Estimation: Infiltration Heat Gain and Loss

Complete guide to infiltration in HVAC load estimation using ASHRAE, CIBSE, and Carrier standards for accurate assessment of uncontrolled air exchange and its impact on heating and cooling loads.

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Digital Tools & Resources

Air Filters Efficiency Classification

ASHRAE 52.2: Filter testing was originated from America in 1930 (ASHVE and AFI code). It was then reviewed and modified in 1967 and 1968. ASRHAE collaborated with American National Standard Institude (ANSI) in 1992 to create ASHRAE-ANSI 52.1. Finally updated to ASHRAE 52.2 in 2007.

Psychrometric Programming Functions

ibrary of psychrometric functions to calculate thermodynamic properties of air for Python, C, C#, Fortran, JavaScript and VBA/Excel

Refrigerants in 2025: Properties, Applications, and Compatibility

As the HVAC and refrigeration industry continues to evolve with environmental regulations and technological advancements, understanding refrigerant properties remains crucial for engineers, technicians, and facility managers. This comprehensive guide provides an updated overview of common refrigerants, their compositions, and applications in today’s market.

Carrier Hap Software

Carrier’s Hourly Analysis Program is two powerful tools in one package – versatile features for designing HVAC systems for commercial buildings AND powerful energy analysis capabilities for comparing energy consumption and operating costs of design alternatives.

Trace 700 Software

TRACE 700 enables building designers to optimize the building, system and equipment designs on the basis of energy utilization and life-cycle cost. The Trane software for TRACE 700 facilitates analysis of the energy and economic effects of virtually any chiller plant configuration by allowing users to manipulate a wide range of variables and create a profile of their specific building.

Download EVAP-COND 5.0: The Ultimate Heat Exchanger Simulation Tool for HVAC Engineers

Whether you’re designing a new heat exchanger, optimizing an existing system, or researching alternative refrigerants, EVAP-COND provides the detailed analysis capabilities needed to make informed decisions. I encourage all HVAC engineers and researchers to explore this powerful simulation tool and experience firsthand how it can transform your approach to heat exchanger design.

Heat Transfer Textbook Download

The book is meant for juniors, seniors, and first-year graduate students. And to those who choose to learn the subject on their own, and to practicing engineers who use it as a reference. Whether one studies alone or with a class, learning means posing, then answering, one’s own questions.

Flexible Duct Calculator

Flexible Duct Calculator based on four different methods. Based on Friction Loss, Based on Duct Diameter, Equivalent Rectangular Duct, Equivalent Round Duct Diameter. Also table of Maximum Recommended Supply Velocity.

Air Change Cfm Calculator

The rate at which air is exchanged (in the premises) represents another method of measuring ventilation capacity & effectiveness. Air exchange rate is typically expressed in Air Changes per Hour – “ACH”. Air changes per hour can be estimated by determining the total air supplied to, and removed from, the premises “total air exchange” or the outdoor (fresh) air supplied to, and removed from, the premises “outdoor air exchange”. We invite you to experience how this calculator can transform your workflow. Whether you’re specifying a new system, troubleshooting an existing installation, or teaching the next generation of HVAC professionals, this tool was built with your needs in mind.

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