Report on Compare Energy & Cost savings of Chilled Beam vs Variable Air Volume Systems

Abstract of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

The research is about the comparison of energy and cost of chilled beam versus variable air volume. The cooling load calculations in the energy saving of VAV are performed. Cost and energy analysis are carried out and it’s evaluated that system which gives a better saving. The VAV could also save much energy which is compared by the different types of the HVAC system and demand for more investment. The water distribution system is known was waterside while airside refers to the air distribution system. There is the following section which explained the cost and the energy-saving od Chilled beams and VAV.

Introduction of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

Variable Air Volume (VAV) of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

Variable Air Volume (VAV) Multiple VAV boxes make up a VAV system that controls the air supply of an individual zone though modulating a damper dependent on the demand of the load. Load demand is determined with the help of a thermostat which triggers the opening or closing of damper and consequently speeding up or slowing down the fan until the static pressure reaches the set-point. To ensure that air temperature is maintained at setpoint during a part load condition, the reheat coil is used. Water reheat and electric reheat are the two kinds of reheat. Hot water from external sources like boiler etc. is used in water rehear while electric reheat use a coil to provide direct heat to the supply air (SCANES, 2016)

Chilled beam of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

Designing efficient water-based systems to provide cooling for a large commercial building like shopping malls, hospitals, and offices, etc. are very important as these systems account for more than 40% of total energy consumption in the buildings. Apart from having high energy expenditure, these systems have very high operating and maintenance costs. A chilled plant has two parts namely the water side and the air side. The chilled water distribution system is known was waterside while the air side refers to the air distribution system. The most commonly used air distribution systems in practice are Chilled Beam (CB) and Variable Air Volume (VAV) Chilled beam.

There are two types of chilled beams which are known

·         Active Chilled Beam (ACB)

·         Passive Chilled Beam (PCB).

In PCB, the heat exchange between the entering air and coil is achieved using natural means where the difference of density between cold and warm air causes air movement through the coil. While in ACB, the air handler is used to supply primary air which induces the room air to pass through the secondary coil and before entering the room it mixes with the primary air. ACB has better performance and is also efficient as compared with PCB due to forced convection (Yau et al , 2018).

Figure: Passive Chilled Beam and Active Chilled Beam

Analysis of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems
Cost-saving of Chilled beam and VAV of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

VAV system is a common system that is used in invasive areas of healthcare facilities. When considering the cost factor for both chilled beam and VAV the initial cost of the chilled beam is higher as compared to VAV. The main cost issues are associated with the secondary chilled water pipe, the beam itself, and the heat exchanger. However, on contrary the operation cost of the chilled beam is lower and in the case of long-term usage chilled beam is more cost-saving instead of high-cost VAV. Here, analysis is carried out to demonstrate that the chilled beam system is potentially better for non-invasive spaces. Chilled beams indicate more advantages such as low energy consumption, regular maintenance, improved comfort, and easy commissioning. There is no specified type of moving parts of chilled beams and it reduces maintenance cost (Yau & Tam, 2018).  Below are some mock calculations provided to explain the cost of VAVs and chilled beam under specified conditions of the office rooms.

1.         Percent reduction in the primary air is 79%.

2.         The average size per room for the chilled beam is 5 ft.

3.         The total estimated cost for the chilled beam in the typical area is $102, 760 at $4.16/SF.

4.         The total estimated cost for VAVs for the specified area is $15078 at $8.51/SF.

5.         The percentage increase in chilled beams is nearly 700%.

The add deduct cost analysis define the initial cost impact of using the VAV system and chilled beam system. the life cycle cost analysis uses the payback period to determine the cost and savings by using these systems (Yau & Tam, 2018).

Energy-saving of Chilled beam and VAV
Energy-saving evaluation of VAV system

The cooling season along with the heating season is supposed. The energy consumptions of the HVAC system could also be written as;

            

By the different assumptions along with the different operations of the mode of fans and the terminal equipment’s which leads the difference of round energy consumption between constant air volume system.

The energy-saving of a variable air volume system is always compared by the constant air volume system;

Energy-saving Chilled beam system of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

A chilled beam is the most important part of the energy-efficient system which is also required the correct primary air system for the savings of energy. Chilled beams are also beneficial for the increased volumetric capacity of the heat of water over air. The water also needs the  to the volume which is the same amount for energy like the air (Tiitus-hvac.blogspot., 2017).

There are two distinct cooling components of the chilled beam;

·         Induced room air

·         Primary air

According to researchers the team also determined the various radiations of the chilled beam system which is also provided for the total energy of saving of 10-21% and it is also depending on the configuration.

The energy savings are up to 12% which is used passive chilled beams system and Midwest condition that is also compared by the traditional system to control air temperature. The separate chiller by the higher chiller of operating temperature which could also provide 11% energy savings.

    Comparison between VAV chilled beam systems

One of the majors constitute of reducing global energy consumption and environmental impact is by reducing consumption of energy at individual levels. the heat transfer characteristics of both chilled beam and VAV system define the characteristics of work and estimate the energy performance. the indoor thermal conditions, configuration, and parallel air volume system are used in these processes. The results of research conducted by Kim et al. (2019) shows that usage of the dedicated outdoor air system, a desiccant wheel, and separate chillers for passive chilled beams induce a significant impact on the relative energy consumption and energy savings (Kima, Tzempelikos, & Brauna, 2019). The passive chilled beams provide more efficient outcomes that are 12% for humid and hot climates and around 20% for the dry and hot climate. The radiative cooling effect between the passive chilled beams varied between 7% and 8% and it affects the indoor thermal conditions and energy savings. The energy modeling system different areas of assessment for the energy savings under climatic zones and passive chilling. Typical validation shows a free-floating temperature with external conditions. The results of the research also indicate that the passive chilled beam system is not capable to provide significant energy savings when compared to the VAV system. the damper system can reduce the load in the passive chilled beam system. chilled beam uses low energy consumption and the reason lies behind the efficient water usage instead of air. Statistics show that HVAC energy cost is approximately $2.33/SF per annum. The full annual energy bill is approximately $ 3, 760, 000 (Yau & Tam, 2018).

Conclusion of Compare Energy & Cost savings of Chilled Beam vs. Variable Air Volume Systems

Summing up all the discussion it is conduced that the comparison of the energy and cost-saving of VAV and the chilled beams is presented. The energy evaluation for the variable air volume is also shown in the calculations form. The cost analysis of VAV and chilled beams is also performed as shown in the above discussion.