Showing posts with label chilled water. Show all posts
Showing posts with label chilled water. Show all posts

Wednesday, July 19, 2017

Integrated Solution for Chilled Water Coil Control

integrated sensors, controller, control valve, actuator for HVAC
Monitrol includes controller, sensors, control valve, and
actuator in a single integrated package.
Image courtesy of Warren Controls
The final control element used for heating or cooling via a heat transfer fluid is going to be a control valve, most often one capable of modulating the fluid flow by precise valve positioning. This control activity requires sensors, the control valve, a controller, and an actuator.

Selecting, installing, and coordinating the operation of these components can be challenging and time consuming, especially when the components are sourced from varied manufacturers. Warren Controls delivers a consolidated solution with their Monitrol line of control valves intended for heat transfer control tasks and related operations. The Monitrol concept involves combining pre-engineered and matched controllers and actuators with flow control valves equipped with built-in sensors for pressure, temperature, or flow. Measurement and control is performed locally, with communications between the local and central controllers exchanging setpoint and performance information. The solution is compact and simplified, enabling easy selection, installation, and startup.

More details are provided in the document included below. There are numerous product variants to accommodate a wide array of field applications. Share your fluid control and heat transfer requirements and challenges with an application expert, combining your own facility and process knowledge with their product application expertise to develop an effective solution.

Tuesday, June 20, 2017

Shell and Tube Heat Exchangers

large shell and tube heat exchangers at oil refinery
These shell and tube heat exchangers are at an oil refinery, but
their application crosses all industry boundaries.
Cars are something which exist as part of the backbone of modern society, for both personal and professional use. Automobiles, while being everyday objects, also contain systems which need to be constantly maintained and in-sequence to ensure the safety of both the machine and the driver. One of the most essential elements of car ownership is the understanding of how heat and temperature can impact a car’s operation. Likewise, regulating temperature in industrial operations, which is akin to controlling heat, is a key process control variable relating to both product excellence and operator safety. Since temperature is a fundamental aspect of both industrial and consumer life, heat management must be accurate, consistent, and predictable.

A common design of heat exchangers used in the oil refining and chemical processing industries is the shell and tube heat exchanger. A pressure vessel, the shell, contains a bundle of tubes. One fluid flows within the tubes while another floods the shell and contacts the outer tube surface. Heat energy conducts through the tube wall from the warmer to the cooler substance, completing the transfer of heat between the two distinct substances. These fluids can either be liquids or gases. If a large heat transfer area is utilized, consisting of greater tube surface area, many tubes or circuits of tubes can be used concurrently in order to maximize the transfer of heat. There are many considerations to take into account in regards to the design of shell and tube heat exchangers, such as tube diameter, circuiting of the tubes, tube wall thickness, shell and tube operating pressure requirements, and more. In parallel fashion to a process control system, every decision made in reference to designing and practically applying the correct heat exchanger depends on the factors present in both the materials being regulated and the industrial purpose for which the exchanger is going to be used.

The industrial and commercial applications of shell and tube heat exchangers are vast, ranging from small to very large capacities. They can serve as condensers, evaporators, heaters, or coolers. You will find them throughout almost every industry, and as a part of many large HVAC systems. Shell and tube heat exchangers, specifically, find applicability in many sub-industries related to food and beverage: brewery processes, juice, sauce, soup, syrup, oils, sugar, and others. Pure steam for WFI production is an application where special materials, like stainless steel, are employed for shell and tube units that transfer heat while maintaining isolation and purity of a highly controlled process fluid.

Shell and tube heat exchangers are rugged, efficient, and require little attention other than periodic inspection. Proper unit specification, selection, and installation contribute to longevity and solid performance. Share your project challenges with application experts, combining your own process and facilities knowledge with their product application expertise to develop effective solutions.

Wednesday, April 5, 2017

Closed Loop Cooling - Alternative Setup Delivers Benefits

Industrial processing often requires the transfer of heat, sometimes into the process, sometimes out of the process. External heat sources are often steam, hot water, or electric heaters. There are also instances where processing machinery either adds heat to the process or requires heat removal (cooling) in order to maintain proper function. If the heat source can accommodate a flowing liquid to provide removal of excess heat, it is a candidate for a closed loop cooling system.

One schematic for a closed loop cooling circuit would show the heat source connected to the piping system, with a pump for circulation and a finned coil located outdoors. The pump moves the heat transfer liquid through the hot area where heat moves from the process to the flowing liquid. The heated liquid continues to flow through the piping system to the finned coil, located outdoors. A fan moves air across the coil to provide heat transfer. The finned coil size would need to be comparatively large, since only sensible cooling using the forced air is employed. The fan capacity would be commensurate with the coil size and the circulating pump rating would be in line with the fluid moving requirements of the system. While this design is fairly simple, there may be a more efficient way to accomplish the heat transfer and deliver what may be beneficial additional features.

Consider a different schematic for the same application. This alternate design employs a closed loop cooling circuit for the heat source, but utilizes a different means of rejecting the heat from the closed loop to the outside air. A plate and frame heat exchanger transfers heat from the closed cooling loop to an open loop circuit that circulates through a cooling tower located outdoors. This scenario maintains the closed loop nature of the equipment cooling circuit, preventing entry of particulates or dissolved gases into the cooling fluid circulating through the process or machinery. Here is what the schematic looks like, courtesy of Delta Cooling Towers .
closed loop cooling system schematic with cooling tower
Closed loop cooling of process heat source using plat and frame heat exchanger and induced draft cooling tower
Courtesy Delta Cooling Towers
The cooling tower offers far greater efficiency than the fan and coil arrangement in the first design. Employing a plastic cooling tower will drastically reduce the life cycle cost over a galvanized steel model and the cooling tower will occupy significantly less space and require less costly support structure than the larger fan and coil arrangement. Total horsepower requirements for the system are reduced. The closed loop will not require any chemical additions for freeze protection because it no longer extends outdoors. This system also provides an element of flexibility, with expansion of the plate and frame heat exchanger a possibility. Cooling tower capacity is also expandable and available for other uses throughout the facility.

There are more details provided in the datasheet included below. Share your heat transfer and cooling challenges with application experts and explore various options. The combination of your process knowledge and experience with their product application expertise will produce an effective solution.