Counterflow (induced draft) systems are considered the most efficient of the two. Crossflow (
Counterflow Cooling Towers
They provide excellent thermal efficiency and allow air to travel vertically over the splash fill. Because they cannot use gravity-fed decks with upward airflow, counterflow models have pressurized spray nozzles to spread the water across the fill.
Both crossflow and counterflow towers have their advantages and the application alone should dictate which type of tower should be used. Crossflow towers will serve better for maintenance access, variable flow, and cold weather operation.
Counterflow (induced draft) systems are considered the most efficient of the two. Crossflow (forced draft) towers distribute hot water perpendicularly to the airflow, while counterflow towers distribute hot water directly into the airflow.
One of the great advantages of counter-current flow is the possibility of extracting a higher proportion of the heat content of the heating fluid. It is important to note that the LMTD value for counter-current flow is much larger than for cocurrent flow at the same terminal temperature (see Figure 1.9).
For cooling tower sizing, the rule of thumb is 3.0 GPM/ton for a 10F delta-T across the tower.
The location you choose for cooling tower installation should be tested in comparison to air intakes and wind patterns for maximum efficiency. Cooling towers should be kept at least 25 feet away from any air intakes. Cooling tower installation should also take building acoustics into consideration.
An induced draft tower typically has fans located at the top of the air outlet. These fans pull cool air through the tower. They get their name from the induction of warm, moist air out of the discharge outlet.
In hot climates, large office buildings, hospitals, and schools typically use cooling towers in their air conditioning systems.
Liquid-cooled engines. When it comes to cooling, liquid-cooled engine bikes come out on the top in terms of efficiency. In this cooling system, a coolant is circulated through the internal passages built into the engine, which absorbs the heat produced by it.
The average cooling tower cost goes between $50,000 and $200,000 but it is always better to make estimates based on your specific needs than look at averages.
In summary, air-cooled chiller advantages include lower maintenance costs, a prepackaged system for easier design and installation, and better performance in freezing temperature. Water-cooled chiller advantages include greater energy efficiency, larger capacities, and longer equipment life.
The first step in selecting a cooling tower is to determine your cooling needs. This involves understanding the heat load that your operations generate, the ambient temperature, as well as the required temperature of the cooled water. These factors will dictate the size and type of the cooling tower needed.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) determines that cooling towers now last between 20-34 years when properly maintained.
For example, while a cooling tower may be sufficient for your building's cooling needs in the winter and fall, during the hotter months of the year, you will need a water chiller to manage your excess heat waste.
Generally we take 1 TR = 400 CFM. As a thumb rule.
How To Measure Cooling Tower Capacity. Measuring the capacity of a cooling tower comes down to a math formula: the product of the rate at which the water flows, specific heat and the temperature difference required, represented as 500 x q x dt/12,000.
By contrast, counter flow is significantly more efficient and, depending on the flow rate and temperature, the heat transfer performance could be up to 15% more efficient, possibly enabling a smaller heat exchanger to be used, saving space and money!
Occurrence of flooding in Reactor Systems
This limit of the stable countercurrent flow is known as flooding. There are several locations within the reactor cooling system where gravity drainage of liquid can be impeded by upward flowing vapor and potentially result in an undesirable flooding situation.
Cooling tower cells must be designed to accommodate a 50% turndown of water flow rate, although some designs may be capable of more turndown.