Hvac Equations (U.S./Metric)
The heating, ventilation, and air conditioning (HVAC) equations. In both U.S. and Metric units.
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.
Non Vapour Compression Cycles
Although work is underway to develop alternative refrigerants and improve refrigerant management strategies, the phase-down of HFCs will impose constraints on vaporcompression equipment that will require trade-offs among cost, efficiency, and safety. These constraints could present market opportunities for alternative space-conditioning technologies. Alternative technologies based on their development status (some technologies are in very early stages of development), potential for energy savings, and other factors that may affect their ability to compete with vapor-compression systems.
Chilled Beam Selection
There are many different designs of chilled beams on the market, which makes the selection and comparison between product types and manufacturers difficult. However, there are technical details that can be compared when making a chilled beam selection.
There are four main steps that should be taken into account when selecting chilled beams
Radiant Chilled Ceiling Selection
There are a number of types of radiant chilled ceilings on the market. Ensuring good thermal conductivity between the cooling element and the other parts of the radiant chilled ceilings is important to ensure maximum performance. The cooling capacity of chilled ceilings is one of the major selection criteria.
Typical Piping For Steam Heating
The piping and radiator connections shown in this section are diagrammatic and illustrate the proper method of making piping connections in steam heating processes.
– Two pipe steam systems radiator connections
– Piping connections for unit heaters (steam)
– Two pipe– #steam trap installations
– Two Pipe Steam Systems Convector Connections
– Exposed #Pipe #Coils– Two Pipe Steam
– One pipe #steam systems radiator connections
– One pipe steam systems #convector connections
– One pipe steam systems convector connections
Steam Trap Explained Totally
There are many types of steam traps each having its unique characteristics and system benefits. Deciding which type of trap to use is sometimes confusing and, in many cases, more than one type can be used. The following is intended to point out system conditions that may be encountered and the characteristics of each type of trap.
Steam Trap – Operation, Advantages, Disadvantages And Primary Applications
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.
Variable Refrigerant Flow (VRF) Benefits
VRF systems are available either as heat pump systems or as heat recovery systems for those applications where simultaneous heating and cooling is required. In addition to providing superior comfort, VRF systems offer design flexibility, energy savings, and cost effective installation.
A VRF system offers flexible installation and energy-saving cooling and heating comfort and should be considered as an alternative to traditional systems for those applications where zoning or part load operation is required.
Metabolic Rates For Typical Tasks
The interrelationships among human beings, ambient conditions, and conditions within the built environment. Metabolic Rates For Typical Tasks
Variable Refrigerant Flow Systems
VRF systems utilize refrigerant as the working fluid and can provide cooling only to multiple indoor fan-coil units connected to a single condensing unit, either cooling or heating to multiple indoor fan-coil units connected to a single heat pump unit, or both cooling and heating simultaneously to multiple indoor fan-coil units connected to a single heat recovery unit.
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
Air Changes Per Hour
The process by which fresh air is introduced and contaminated air is removed from an occupied space is termed ventilation. Ventilation is necessary to provide a continuous supply of oxygen. Air changes per hour (ACH) is a measure of the air volume added to or removed from a space in one hour, divided by the volume of the space.
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.
Calculating Pump Energy Savings
For heating or chilled water systems serving air conditioning plant, the requirement for maximum heating or cooling occurs only at start up, or on infrequent peak design days. For the majority of the time, a reduced heating or cooling output will suffice. During these periods there is potential to pump less water, thereby reducing the annual pump energy consumption.
Data Center Design Considerations (HVAC)
A data center design encompasses architectural (rack layout), structural, mechanical, electrical, fire protection, and cabling system. Sustainable design is essential because a data center can consume 40–100 times more electricity compared to a similar‐size office space.
Solar Heat Transfer Topics
The role of convection and conduction heat transfer in the performance of solar systems is obvious. Radiation heat transfer plays a role in bringing energy to the earth, but not so obvious is the significant role radiation heat transfer plays in the operation of solar collectors.
Hot Water Boilers Control
Hot Water Boiler Controls, Zone Controls, Three-Way Valve Controls, Room Thermostat Controls, Room Thermostat Controlling Pumps, Indoor/Outdoor Control of Boiler, Zone Control by Circulator Control, Three-way Valve, Control through Indoor/Outdoor Stat, Control through Return Water, Indoor/Outdoor Controls
Life Cycle Cost Analysis Method
The life-cycle cost analysis method is the most commonly accepted method to assess the economic benefits of energy conservation projects over their lifetime. Typically, the method is used to evaluate at least two alternatives of a given project (for instance, evaluate two alternatives for the installation of a new HVAC system: a VAV system or a heat pump system to condition the building). Only one alternative will be selected for implementation based on the economic analysis.
Refrigerant Piping Requirements
This guide focuses on systems that use Refrigerant-22 (R-22). While the general requirements are the same for systems that use other refrigerants, velocities and pressure drops will differ.
Large Chilled Water Systems
Large chilled-water systems with six or more chillers (Figure below) have different challenges than smaller systems. Examples of these types of systems are commonly found on campuses with multiple buildings, downtown districts, and mixed-use residential and commercial developments.
Mid Sized Chilled Water Systems
In addition to the design decisions faced by the small chilled-water system designer, the following objectives may be encountered by the mid-sized system designer.
Small Chilled-Water Systems
A common design goal for the small chilled-water system with one or two chillers (Figure below) is to minimize complexity while balancing energy consumption goals. Smaller chilled-water systems may have smaller budgets allotted for operation and maintenance and may run unattended more often than larger systems. Keeping it simple, while capitalizing on chilled water advantages, is the hallmark of a successful project.
Chiller Plant Control
It is important to understand that no matter how good the system design is, adequate controls are necessary for all the components to operate properly as a system. It is equally important to understand that you cannot “control your way out of a bad system design.
Ice Storage Systems
Thermal energy storage (TES) involves adding heat (thermal) energy to a storage medium, and then removing it from that medium for use at some other time. This may involve storing thermal energy at high temperatures (heat storage) or at low temperatures (cool storage).
Copeland Refrigeration Manuals Download
This is a five series of publications comprising the Emerson Climate Technologies, Inc. Refrigeration Manual. Although each separate part covers a specific area of refrigeration theory and practice, each successive publication presumes a basic understanding of the material presented in the previous sections.
Daikin Revit Files
DAIKIN APPLIED RESOURCE LIBRARY – REVIT FILES
Rooftop Systems
Air Handlers – Outdoor
Air Cooled Chillers
Water Cooled Chillers
Fan Coils
Self-Contained
Water Source Heat Pump
Unit Ventilators
Major Hvac Systems and Equipment
A comprehensive list of all the major HVAC system types and related equipment
Hvac System Components
Refrigeration and HVAC Systems and Equipment components help system designers and operators to select and use equipment that is the best fit for a particular application or controlling scenario.
Piping Tools (Excel Files)
More than 165 spreadsheets (excel xls files) for a comprehensive range of calculation in Fluid, Thermal and piping engineering.