The chilled water coil in the doas in your diagram is sharing the same chilled water loop as the CBs. This in practice would not work as the DOAS would need 44ish degree water to acomplish dew point control of the primary air supply. A three-way valve mixing loop would be necessary for the CBs to maintain a sensible only CHW loop. As the chiller still has to produce 44 degree water, it sees no lift reduction gained efficiency due to the warmer chilled water requirements of the CBs.
Yes, the CHW temperature would be different, as the Chilled Beams need to avoid the formation of condensation, while the DOAS will be removing moisture from the incoming air. The pictures are diagrammatic, and don't show all control points and valves. Great observation. Thanks
10:00 You saying that VAV will reheat already cooled air when chill beams will modulate the water flow instead. But in the 4 pipe chill beam system, the 2 heating pipes are doing the same thing - reheating already cooled air. Please explain
You're correct that both systems use reheat strategies. The best application for Chilled Beams are on spaces with high Sensible Loads. Heating is not recommended when using passive chilled beams. Active beams can be used for heating in moderate climates, or a hot water coil can be added to the primary duct that feeds multiple spaces with the same load profile, as this also saves on the added cost of running heating hot water piping to each chilled beam. The annual difference in reheat energy between a VAV system and an a 4-Pipe Active Beam depends on the primary airflow delivered to the ACBs, the minimum airflow setting for the VAV terminals, the primary air temperature, whether there is any temperature reset strategy being used for the primary-air in either system, and the number of hours when the zones experience low cooling loads. (VAV systems can benefit by using parallel fan-powered VAV terminals to draw warm air from the ceiling plenum as the first stage of heating, thereby reducing reheat energy use.) Also, VAV System are better at implementing a Demand Controlled Ventilation (DCV) strategy. Thanks for the question. Great Observation.
500 is a constant that is derived by the weight of water 8.33 Lbs multiplied by the specific heat 1.0 multiplied by 60 minutes/hour. (8.33 x 1 x 60 = 500)
Hi everyone, As a fellow lifelong learner, I was captivated by this educational content. To make it more accessible, I've summarized the key points using an AI tool, with all credit to MEP Academy. I'd love to hear your thoughts and insights in the comments below. 🔹 Chilled Beams Types: The video elucidates two chilled beam types: active and passive. Active beams, with one or two coils in a metal housing, leverage primary air from an air handler to induce airflow. Conversely, passive beams utilize natural convection, operating without fans. 🔹 Ventilation Requirements: It emphasizes the vital need for ventilation in all occupied spaces as mandated by ASHRAE 62.1. Active beams directly incorporate ventilation air, inducing airflow, while passive beams rely on external ventilation sources. 🔹 Cooling Mechanism: The process of how chilled beams cool spaces is intriguing. Water flows through the beams' coils, chilling the surrounding air. This denser, cooler air naturally circulates, effectively replacing warmer air. 🔹 Beam Sizes and Capacities: Active chilled beams are versatile, ranging from 2 to 10 feet in length, with cooling capabilities of 600 to 1100 BTUs per foot. Passive beams, while efficient, typically offer lower output capacities. 🔹 System Types: The video covers both two-pipe and four-pipe systems. In two-pipe systems, a shared coil is used for both heating and cooling. Four-pipe systems, on the other hand, have distinct coils for each function. 🔹 Air Stratification and DOAS: Here, air stratification's dynamics and the role of DOAS (Dedicated Outside Air System) or AHU (Air Handling Unit) in managing ventilation and latent loads are elucidated. 🔹 Chilled Water Supply and Humidity: The discussion includes the chilled water supply's temperature range (55 to 62°F) and the criticality of keeping it above the room's dew point to avert condensation. 🔹 VAV System Comparison: A comparison is drawn between chilled beam systems and Variable Air Volume (VAV) systems, underscoring the former's energy and space efficiency advantages. 🔹 Dew Point Transmitters and Moisture Sensors: The video underscores the significance of dew point transmitters and moisture sensors in chilled beam systems to prevent condensation and the ensuing potential for water damage. 🔹 Benefits of Active Chilled Beams: The benefits of active chilled beams are numerous, including reduced sizes of ducts and air handlers, elimination of reheat coils, energy efficiency, and quieter operations. 🔹 Cost Considerations: It's noted that the installation costs for chilled beam systems might surpass those of conventional VAV systems, owing primarily to the extensive chilled water piping requirements and the potential need for additional beams to meet specific demands. Looking forward to your feedback and any further insights you might have!
As we all technologies, chilled beams have design parameters that define when they're appropriate. As engineers this is one more tool to use when the conditions are applicable. This technology has saved a lot of energy for many companies.
What other devices/strategies should be used to prevent condensation in the CHW pipes? besides insulation and moisture sensors, I'm also referring to hot climate
thank you for the excellent presentation
You're Welcome
The chilled water coil in the doas in your diagram is sharing the same chilled water loop as the CBs. This in practice would not work as the DOAS would need 44ish degree water to acomplish dew point control of the primary air supply. A three-way valve mixing loop would be necessary for the CBs to maintain a sensible only CHW loop. As the chiller still has to produce 44 degree water, it sees no lift reduction gained efficiency due to the warmer chilled water requirements of the CBs.
Yes, the CHW temperature would be different, as the Chilled Beams need to avoid the formation of condensation, while the DOAS will be removing moisture from the incoming air. The pictures are diagrammatic, and don't show all control points and valves. Great observation. Thanks
Excellent presentation.
Glad you liked it. Thanks for watching
10:00 You saying that VAV will reheat already cooled air when chill beams will modulate the water flow instead. But in the 4 pipe chill beam system, the 2 heating pipes are doing the same thing - reheating already cooled air. Please explain
You're correct that both systems use reheat strategies. The best application for Chilled Beams are on spaces with high Sensible Loads. Heating is not recommended when using passive chilled beams. Active beams can be used for heating in moderate climates, or a hot water coil can be added to the primary duct that feeds multiple spaces with the same load profile, as this also saves on the added cost of running heating hot water piping to each chilled beam. The annual difference in reheat energy between a VAV system and an a 4-Pipe Active Beam depends on the primary airflow delivered to the ACBs, the minimum airflow setting for the VAV terminals, the primary air temperature, whether there is any temperature reset strategy being used for the primary-air in either system, and the number of hours when the zones experience low cooling loads. (VAV systems can benefit by using parallel fan-powered VAV terminals to draw warm air from the ceiling plenum as the first stage of heating, thereby reducing reheat energy use.) Also, VAV System are better at implementing a Demand Controlled Ventilation (DCV) strategy. Thanks for the question. Great Observation.
Great presentation.
Glad you liked it! Thanks for watching.
Thanks for the great video. How is the 500 calculated in the Q equation?
500 is a constant that is derived by the weight of water 8.33 Lbs multiplied by the specific heat 1.0 multiplied by 60 minutes/hour. (8.33 x 1 x 60 = 500)
Hi everyone,
As a fellow lifelong learner, I was captivated by this educational content. To make it more accessible, I've summarized the key points using an AI tool, with all credit to MEP Academy. I'd love to hear your thoughts and insights in the comments below.
🔹 Chilled Beams Types: The video elucidates two chilled beam types: active and passive. Active beams, with one or two coils in a metal housing, leverage primary air from an air handler to induce airflow. Conversely, passive beams utilize natural convection, operating without fans.
🔹 Ventilation Requirements: It emphasizes the vital need for ventilation in all occupied spaces as mandated by ASHRAE 62.1. Active beams directly incorporate ventilation air, inducing airflow, while passive beams rely on external ventilation sources.
🔹 Cooling Mechanism: The process of how chilled beams cool spaces is intriguing. Water flows through the beams' coils, chilling the surrounding air. This denser, cooler air naturally circulates, effectively replacing warmer air.
🔹 Beam Sizes and Capacities: Active chilled beams are versatile, ranging from 2 to 10 feet in length, with cooling capabilities of 600 to 1100 BTUs per foot. Passive beams, while efficient, typically offer lower output capacities.
🔹 System Types: The video covers both two-pipe and four-pipe systems. In two-pipe systems, a shared coil is used for both heating and cooling. Four-pipe systems, on the other hand, have distinct coils for each function.
🔹 Air Stratification and DOAS: Here, air stratification's dynamics and the role of DOAS (Dedicated Outside Air System) or AHU (Air Handling Unit) in managing ventilation and latent loads are elucidated.
🔹 Chilled Water Supply and Humidity: The discussion includes the chilled water supply's temperature range (55 to 62°F) and the criticality of keeping it above the room's dew point to avert condensation.
🔹 VAV System Comparison: A comparison is drawn between chilled beam systems and Variable Air Volume (VAV) systems, underscoring the former's energy and space efficiency advantages.
🔹 Dew Point Transmitters and Moisture Sensors: The video underscores the significance of dew point transmitters and moisture sensors in chilled beam systems to prevent condensation and the ensuing potential for water damage.
🔹 Benefits of Active Chilled Beams: The benefits of active chilled beams are numerous, including reduced sizes of ducts and air handlers, elimination of reheat coils, energy efficiency, and quieter operations.
🔹 Cost Considerations: It's noted that the installation costs for chilled beam systems might surpass those of conventional VAV systems, owing primarily to the extensive chilled water piping requirements and the potential need for additional beams to meet specific demands.
Looking forward to your feedback and any further insights you might have!
Schooling setting that's very comfortable
Chilled beams can work in schools.
Good luck in a hot climate.
As we all technologies, chilled beams have design parameters that define when they're appropriate. As engineers this is one more tool to use when the conditions are applicable. This technology has saved a lot of energy for many companies.
What other devices/strategies should be used to prevent condensation in the CHW pipes?
besides insulation and moisture sensors, I'm also referring to hot climate