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White Papers --- Wrap-Around Heat Pipe, Dehumidification

 

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"Wrap-Around Heat Pipes In Humid Climates" A New Article in ASHRAE Journal

A recent issue of the ASHRAE Journal includes an article titled, "Wrap-Around Heat Pipes in Humid Climates", co-authored by our Regional Sales Manager, Drew Elsberry. It covers the various energy requirements within ASHRAE Standard 90.1 - which apply to nearly all state and local building codes - and focuses on the allowance of wrap-around heat pipes as an exception to mandatory air-to-air energy recovery. It discusses the scenarios in which such a design would make sense, and then dives deeper into the use of controllable heat pipes to optimize energy savings. To learn more, click on the link below.

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Controllable heat pipes

Effectively Utilizing Control Valves to Optimize Wrap-Around Heat Pipes

Fully controllable heat pipes, a specialty of HPT, are an effective way to recover as much heat as possible to provide maximum precool and reheat without exceeding set-point. This also allows for maximum reheat at part load conditions. Up to four stages of control are feasible, allowing the design engineer to meet desired conditions at varying loads. This paper focuses on controllable wrap-around heat pipes and how to properly size a system for more frequent part load conditions to really optimize savings.

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psychrometric Chart

Optimizing Wrap-Around Heat Pipes

Wrap-around heat pipes are popular because of their economic benefits and simplicity. While software for heat pipe product selections is available, the effect on cost is not as easily obtainable. This paper explains how to determine simple payback as different engineering and costing parameters are adjusted.

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Chilled Water Systems

Neutral Air Units with Heat Pipes in Chilled Water Systems

This paper focuses on wrap-around heat pipes’ energy and psychrometric advantages, and also provides compelling reasons to use these units to supply neutral air in all dedicated outside air systems. Neutral supply air has its advantages, but a concern that might limit its application is that more energy is required. That is certainly true for traditional systems that cool and then reheat, but wrap-around heat pipes are a proven method to get the neutral condition with significantly LESS energy usage.

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Tropical

Critical Dehumidification in tropical Locations

ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality, has recently been tightening acceptable design practices to specifically limit the relative humidity. The standard defines a very low load Sensible Heat Ratio (SHR) for the equipment to meet and sets guidelines for relative humidity (RH). The paper discusses how a wrap-around heat pipe can provide exactly the same psychrometrics as when reheat is used to control humidity, but without the high energy costs.

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Outside Air System

Optimizing 100% Outside Air Systems with Heat Pipes

Heat pipe wrap-around systems are cost effective, energy efficient, and easily applicable to 100% outside air systems to help the designer meet ASHRAE Standards 62.1- 2010 and 90.1-2010 in new buildings. The wrap-around also helps improve HVAC system performance, Indoor Air Quality (IAQ), and energy efficiency in existing buildings by increasing dehumidification and/or ventilation effectiveness. This paper discusses the design process for heat pipe applications, and the advantages of a heat pipe equipped system, such as downsizing cooling coils and using little or no new reheat energy.

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Coil Pump Around

Coil Pump-Around Systems Compared to Wrap-Around Heat Pipes

This paper compares the life cycle cost between a Water Pump-Around System and a Wrap-Around Heat Pipe via four types of systems. The specific life cycle costs examined are capital costs, maintenance costs and energy costs. Other less quantifiable considerations valuable to the building owner are also discussed, which can be even more important than the economic factors.

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DOAS

ASHRAE’S DOAS Webcast: A Deeper Examination of the Role of Heat Pipes

On April of 2012, ASHRAE conducted a webcast to publicize the concept of Dedicated Outside Air Systems, an alternative to Variable Air Volume Systems (VAV). This paper picks up where the webcast ended to provide a deeper and more comprehensive understanding of the value of Wrap-Around Heat Pipes.

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