Fundamentals & Engineering
Hvac Air Volume Calculation
The air volume for an HVAC system is calculated from the sensible heat in the conditioned space. For the typical heating and cooling unit, the calculation is for cooling because more air is needed to cool a space than to heat it. If the conditioned space can be properly cooled with a given amount of cfm, then the space can be heated correctly with the same amount of cfm.
Thermal Storage (HVAC)
Thermal energy may be stored in three main ways: – Sensible Storage – Latent Storage – Thermo-Chemical Storage. In addition, the two common thermal storage strategies employed are: – Load Levelling Strategy – Load Shifting Strategy
Hydropneumatic Tank Sizing
Hydropneumatic tanks are primarily used in a domestic water system for draw down purposes when the pressure booster system is off on no-flow shutdown (NFSD). The NFSD circuitry turns the lead pump off when there is no demand on the system. While the system is off in this condition, the hydropneumatic tank will satisfy small demands on the system. Without the tank, the booster would restart upon the slightest call for flow such as a single toilet being flushed or even a minute leak in the piping system. Hydropneumatic tank sizing is dependent on two factors: – Length of time you wish the pumps to remain off in a no-flow situation. – The tank location in relation to the pressure booster.
Pump Sizing Core Concepts
Pump sizing involves matching the flow and pressure rating of a pump with the flowrate and pressure required for the process. The mass flowrate of the system is established on the process flow diagram by the mass balance. Achieving this mass flowrate requires a pump that can generate a pressure high enough to overcome the hydraulic resistance of the system of pipes, valves, and so on that the liquid must travel through. This hydraulic resistance is known as the system head.
Hvac Equations (U.S./Metric)
The heating, ventilation, and air conditioning (HVAC) equations. In both U.S. and Metric units.
Expansion Tanks
How does Boyle’s law relate to sizing expansion tanks in domestic hot water systems? what size expansion tank is required?
Expansion Tank Sizing Formulas
Expansion tanks are a necessary part of all closed hydronic systems to control both minimum and maximum pressure throughout the system. A comprehensive review of tank types and sizing procedure for expansion tanks.
Primary Secondary Pumping
– What is Primary-Secondary Pumping? – PRIMARY-SECONDARY BASICS. – PRIMARY-SECONDARY RULES, DEFINITIONS. WHEN TWO PIPING CIRCUITS ARE INTER-CONNECTED, FLOW IN ONE WILL CAUSE FLOW IN THE OTHER, T0 A DEGREE DEPENDING UPON THE PRESSURE DROP IN THE PIPING COMMON T0 BOTH.
4-Pipe And 2-Pipe Heating And Cooling Plants
A 4-pipe heating and cooling plant contains both central heating and cooling equipment and is capable of delivering heating water and chilled water to the building simultaneously through four pipes (one heating water supply, one heating water return, one chilled water supply, and one chilled water return). Heating and cooling equipment within the building that is connected to a 4-pipe system will have four pipe connections, unless the equipment provides either heating only or cooling only. In this case, the equipment would have only two pipe connections.
Constant Air Volume (CAV) Systems
HVAC air systems can be either centralized or decentralized. Centralized air systems receive their cooling and heating energy from a remote central plant. Decentralized HVAC air systems contain the central heating and cooling plant equipment within the air system itself. HVAC air systems can also be constant air volume (CAV) or variable air volume (VAV). CAV systems deliver constant supply airflow at a variable temperature. VAV systems deliver variable supply airflow at a constant temperature. CAV and VAV air systems can be further subdivided into systems that condition a single temperature zone and systems that condition multiple temperature zones.
Standards & Compliance
HVAC Ventilation Design: Lift/Elevator Pressurization
Complete guide to HVAC lift/elevator pressurization design using BS 5588-4 standards covering pressure control, airflow calculations, and elevator system integration for effective emergency vertical transportation protection.
HVAC Ventilation Design: Staircase Pressurization + Relief Vent Sizing
Complete guide to HVAC staircase pressurization and relief vent sizing design using ASHRAE and BS standards covering pressure control, airflow calculations, and relief system integration for effective emergency egress protection.
HVAC Ventilation Design: Corridor/Lift Lobby/Atrium Make-Up/Pressurization
Complete guide to HVAC corridor, lift lobby, and atrium make-up air and pressurization design using CIBSE and ASHRAE standards covering pressure control, airflow calculations, and fire safety integration for effective emergency protection.
HVAC Ventilation Design: Atrium Smoke Extract
Complete guide to HVAC atrium smoke extraction design using CIBSE and ASHRAE standards covering smoke layer management, extraction calculations, and advanced fire safety integration for large-volume space protection.
HVAC Ventilation Design: Corridor/Lift Lobby Smoke Extract
Complete guide to HVAC corridor and lift lobby smoke extraction design using CIBSE fire engineering standards covering smoke removal, pressure management, and life safety system integration for effective emergency ventilation.
HVAC Ventilation Design: Car Parking CO System
Complete guide to HVAC car parking CO detection systems using NFPA 720 standards covering carbon monoxide monitoring, alarm systems, ventilation integration, and safety protocols for parking facility protection.
HVAC Ventilation Design: Car Parking Make-Up Ventilation Rate By Velocity
Complete guide to HVAC car parking make-up ventilation design using ASHRAE velocity-based methods covering air movement calculations, system integration, and performance optimization for effective parking facility ventilation.
HVAC Ventilation Design: Car Parking Extract Ventilation Rate
Complete guide to HVAC car parking extract ventilation design using CIBSE and BS standards covering CO control, air change rates, and specialized applications for safe and efficient parking facility ventilation systems.
HVAC Ventilation Design: Commercial Kitchen Ventilation Rates (Hood/Canopy, Ceiling Extract/Makeup)
Complete guide to HVAC commercial kitchen ventilation design using ASHRAE, CIBSE, and VA standards covering hood exhaust rates, makeup air requirements, and specialized applications for effective contaminant control and energy efficiency.
HVAC Ventilation Design: Tobacco/Smoking Area Ventilation Rates
Complete guide to HVAC smoking area ventilation design using CIBSE standards covering high-performance ventilation rates, specialized system requirements, and health protection strategies for tobacco use areas.
Digital Tools & Resources
Cooltools Software Download
– Cycle analysis (process design) – comparison of one stage direct expansion cycle and one stage flooded cycle. – System sizing – calculation of component sizes from general criteria. – System simulation – calculating operating conditions in a system with known components. Component calculations – calculation of – components efficiencies and outlet conditions. – Evaluation of operation – evaluation of system efficiency. – Process investigation – e.g. moist air calculations.
Refrigerant Ph Diagram (Part 2)
This article is a continuation of our older article, which was well received by users, so we decided to update the P-H Diagram list and provide you with a more complete list of the world’s commercial refrigerants. You can easily access the high quality refrigerant chart by clicking on the refrigerants listed in the table.
Carrier Plv Pro Download
Carrier’s PLV Pro is a software tool that empowers consulting engineers to make objective and informed decisions about their chiller plant design that go beyond Full Load and IPLV metrics. Results are provided in a professional report or .csv format for further analysis. The tool is for professionals who need a quick and free-of-charge alternative to detailed energy modeling analyses.
Coolselector Download
Coolselector®2 (from Danfoss company) helps to optimize energy consumption and increase efficiency in any HVACR system. Run unbiased calculations based on a set of operating conditions — such as cooling capacity, refrigerant, evaporation, and condensation temperature — and then select the best components for your design.
Air Conditioning Condensate calculator
Air conditioning condensate is the water that is produced as a result of the cooling process in an air conditioning system. When the air conditioning system cools the air in a building, it removes moisture from the air, which condenses on the cool coils of the air conditioning system. This condensation is collected and drained away through a condensate drain pipe. The water that is collected in the condensate drain is typically referred to as air conditioning condensate.
Pipe Pressure Drop Calculations: Essential Equations and Guidelines
Explore the essentials of pipe pressure drop calculations, including key factors affecting pressure drop, commonly used equations, and practical tips for optimizing fluid transportation systems. Learn about software and tools that can assist in streamlining your calculations and enhance the efficiency of your projects. In this blog post, we discussed the importance of understanding pipe pressure drop calculations and their relevance across various industries. We introduced key factors affecting pressure drop, such as pipe diameter, length, flow rate, fluid properties, and pipe roughness. We also examined several equations for calculating pressure drop, including the Darcy-Weisbach, Hazen-Williams, and Colebrook-White equations, discussing their applicability and limitations.
mcquay duct sizer Download
The McQuay Duct Sizer is a specialized software tool designed for HVAC professionals to assist in the accurate and efficient sizing of air ducts. This tool is essential for ensuring optimal performance and energy efficiency in HVAC systems. The McQuay Duct Sizer is available for free download.
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
Download HVAC-Cx: The Essential Building HVAC Systems Commissioning Tool
As buildings continue to evolve toward higher efficiency and more sophisticated control strategies, tools like HVAC-Cx become increasingly valuable. The software’s ability to systematically detect faults, prioritize issues, and assist with active commissioning represents a significant advancement in building operations technology.