Buy and choose a cooling tower

Buy a cooling tower

Selecting and purchasing a cooling tower is a sensitive and important process in selecting refrigeration equipment. The cooling tower has a great impact on the performance of other refrigeration equipment such as compression and absorption chillers, air conditioners and fan coils. The right choice in the installation of a building or a large industrial plant must have many sensitivities. Purchase of industrial and refrigeration equipment must be done in accordance with standard design principles. The purchase of a large refrigeration machine that has an important task must be done according to certain criteria.

Determining the rules during the process of selecting and purchasing a cooling tower is one of the most important principles of this work. Refrigeration machines are bought and sold by many companies today. Appearance quality of products, company resume and customer satisfaction are the most important tools for checking a company's activity chart. After selecting a few reputable brands that are preferably manufacturers, you should go to the final decision stage. In the final selection stage, use all the technical and quality tools of a company to finalize this issue. Hasty decisions in areas similar to this can have serious implications.

Tools for checking the power of a manufacturer in the production of cooling towers

Having the necessary expertise in the field of fluid engineering and heat transfer
Checking the resume of the company in the completed projects
Field visit of the production line and construction of the cooling tower or any similar equipment
Careful review of the plan and proposal submitted by the company and the technical capability of the collection in displaying technical details
Repeat calls and check various design and production items according to your specific requirements

Different stages of buying and choosing a cooling tower

Determining the general design conditions and determining the exact design parameters (inlet, outlet temperature, etc.)

Determining the refrigeration or cooling capacity according to the design parameters

Select the appropriate type and model of cooling tower according to the limiting conditions (environmental conditions or design)

Consulting with related designers and engineers who have sufficient engineering knowledge.

Review the data and final check of data sheets and sample calculations

Determining the initial costs of purchase and estimating the ancillary costs of periodic maintenance and service

General economic feasibility (measurement of economic ability) according to the set cost chart

Location of the cooling tower installation site in accordance with the installation principles

Detailed description of the buyer's duties in maintaining the cooling tower

The first important step in buying a cooling tower

The main step in purchasing a new cooling tower or cooling tower is to determine its performance or equipment capacity. Determining the cooling tower capacity is like determining the volume of a water tank. The capacity of the cooling tower is in fact the power and ability of this device to cool water.

The following four parameters must be specified to determine the capacity of an important cooling tower:

Condenser water flow rate (flow rate and volume of water in rotation) in gallons per minute or cubic meters per hour
Cooling tower return temperature or condenser inlet temperature in Celsius or Kelvin
The water temperature of the cooling tower or condenser outlet in degrees Celsius or Kelvin
Humid ambient temperature or wet bubble temperature (saturated air temperature with relative humidity 100)

There are differences between inlet and outlet water temperatures, condenser and ambient or inlet humid temperature. Determining the standard inlet and outlet temperatures of the design as well as determining the humid ambient temperature requires engineering knowledge. Depending on the range (temperature changes) and the amount of water flow, the total amount of BTU per hour of heat dissipation capacity in the cooling tower is determined. With the above information, any manufacturer and designer of refrigeration systems can determine the capacity of the cooling tower. By determining this parameter, the main step in purchasing a water cooling chiller will be taken.

The second step is to buy a cooling tower

Estimating the capacity and determining the strength of the cooling tower is the most important part in purchasing and selecting this product. The most basic step for buying any industrial equipment is to do the right capacity, but this is not a necessary and sufficient condition. The next step in buying a cooling tower is to determine the shape and type of cooling tower, which should be acceptable. To know which type of cooling tower can be suitable for a basic purchase, it is necessary to know the details of each type of cooling tower. Below we review the general classification of types of evaporative refrigeration systems (cooling towers).

General classification of existing cooling tower models

Suction or blowing cooling tower (licensed): Cooling tower with forced air flow system that has a blowing or suction fan.
Natural cooling tower (without fan or impeller): Cooling tower with natural air circulation system (open air) that has no impeller.

Types of cooling towers depending on the type of fan suction

Impeller / forced fan: has an axial impeller with bottom-up air intake system
Centrifugal / forced fan: includes aeration system equipped with a screw impeller or centrifuge
Impeller / Induction Fan: Has an axial impeller with top-down air intake system

Select the cooling tower according to the arrangement of the weather collision flow

Cross or vertical flow (cross flow): The collision of air with water at right angles or perpendicular (crossflow)
Reverse or heterogeneous flow (reverse flow): Reverse current contact (counter flow)

Buy a cooling tower based on the assembly method

Factory assembly: Manufactured and made in the factory or workshop for the production of cooling towers
Field erection or local assembly: Final assembly on site outside the factory (assembly on site)

Purchase and select the cooling tower of choice according to the structure of the device body

All wooden body
Body with galvanized steel sheets
Composite structure of steel with stainless steel bottom pan (stainless steel top pan for cross tower)
All stainless steel structure (stainless steel)
Fiberglass body (reinforced plastic or fiberglass)
Concrete / masonry structure (in the form of a narrow or hyperbolic waist cylinder)
Fiberglass with concrete or cement bottom pan (in the form of large rectangular cooling towers)

Description of Table 1.1 (Selecting the type of structure of the cooling tower body)

The table above shows the types of construction available for different types of flow and suction layouts. As mentioned in previous articles, wood and concrete cooling towers are not typically used in small air conditioning and industrial systems unless the requirements require the use of a high capacity of this equipment (more than 2000 tons) or the aesthetic aspect of the tower. Not very important. When the acceptable option to buy and choose a cooling tower is nothing but galvanized tower and fiberglass, it is recommended not to lock these two models in your choice. These choices (steel or fiberglass body) are recommended by all cooling tower manufacturers . However, choosing the right cooling tower for a composite or steel body can increase costs by 20% to 40%.

Description of Table 1.2 (useful life of cooling tower)

As Table 1.2 shows, the cooling tower life of fiberglass and steel systems increases by 20 to 33% compared to other options. That means a great investment. Factory assembly towers are easier and faster to install and cheaper. Therefore, field assembly towers are less used for the air conditioning system, unless the system load is more than 2000 tons.

Estimate the total cost of purchasing a cooling tower

Estimating the initial costs in the cooling tower purchase process is of great importance to Carrefour. Estimating and calculating the amount of initial expenses is one of the most important items in determining the budget. When setting up a cooling system, in addition to the refrigeration source (chiller or cooling tower), ancillary equipment also has a large impact on the final price of the project. Auxiliary equipment for cooling systems includes pipes, elbows, collectors, one-way valves, pumps, tanks, and electrical equipment such as control panels. Equipment costs are collected directly from their vendors and installation and execution costs are collected from local contractors. VAT is included in the cost of purchasing, which should be considered by sellers. In the discussion of the final implementation and installation of refrigeration equipment, the insurance amount equal to 15 to 20% must be considered by the contractor.

Factors influencing the cost of installing cooling towers

Location foundation and support system or supporting structure
Circulator pump and water circulation between condenser or converter circuit and cooling tower
One-way valves and gate valves to adjust the flow rate of circulating water
Compensatory water purifier or resin hardener to reduce scale deposition of internal components
Compensatory water source or injection water storage source
Cost of demolition and repair of the previous structure or device
Provide required power (three-phase or single-phase)
Preparation and design of control panel for commissioning and protection of electrical equipment
Controllers and control equipment in adjusting the amount of bleed or compensating water and the amount of aeration
Plumbing equipment including: elbow - collector - valve or valve - flange - support and insulation
Electrical start-up equipment: power cable - socket - miniature switch - contactor - bimental and ...
Piping and piping fee between condenser or heat exchanger and cooling tower
Electrical and cabling fee for electrical equipment to control panel and electrical source

Periodic or annual cooling tower costs

As soon as the cooling tower is put into operation and commissioned, two recurring annual costs must be covered in each period of the tower purchase life. Energy costs and maintenance costs are the most important costs of the post-purchase period. Shelf life is the framework by which a tower can be profitable for its owner. Therefore, if the cost of operating and maintaining a piece of equipment exceeds its purchase, its economic (useful) life is over. The cooling tower is physically healthy in its useful life. The useful (economic) life of all types of cooling towers and condenser pumps is presented in Table 1.2 .

Energy cost requires the identification of two quantities:

1. Electricity consumption of tower and condenser pump
2. Unit cost of energy

A condenser pump must be considered in a thorough evaluation and comparison of alternative cooling towers. Because different towers impose different pressure drops on the pumps, the cost of this energy difference must be included in the cost analysis. To determine the energy of the condenser tower and pump, the first step is to determine the load of the condenser water system in terms of refrigeration tone and a function of ambient temperature with changes of 5 degrees. The input power of the condenser water pump and cooling tower must be calculated in kilowatts. Then multiplied by the hour consumed, electricity consumption is obtained in kilowatt hours (KWh).

Non-recurring costs of repairing and replacing parts after purchasing a cooling tower

Non-recurring costs represent repair and replacement costs that occur at longer intervals throughout the year. For example, a galvanized bottom and top pan in an induction suction crossover tower needs to be repaired or replaced after 10 years of operation. These types of costs must be specified and the year in which they occur must be estimated. The comparison of operating cost, maintenance and total energy for the cooling tower and its condenser pump over the service life of the system is calculated according to Equation 1.1.

Periodic cooling tower cost = {(annual maintenance cost + annual energy cost) x (useful life)} + (total repair / replacement cost) + C

Cost of capital (capital) = C

Executive guarantees and CTI certifications

Except for field-mounted cooling towers with very specially designed refrigeration systems, air conditioning cooling towers must comply with the executive certifications of the Institute of Cooling Technology (CTI) and its 201 standard. Compliance with the design and purchase of the cooling tower with CTI standards guarantees the correct choice and the basic operation of the condenser. CTI certifications eliminate the need for a cooling tower field test. These certifications actually minimize the place of any error coefficients and errors in the cooling tower purchase process. The list of authorized CTI standards can be seen in Table 1.3. If you are looking to buy and choose principles, be sure to study these standards and research in different topics.

Economic evaluation of cooling tower replacement systems

Life cycle cost estimation is the best way to compare cooling tower alternatives, which provides a consistent method for analyzing the economic aspects of a tower and creates a realistic comparison to select the most efficient tower with the lowest life cycle cost. This process is basically simple and only requires evaluating the tower with the same criteria that lead to one-on-one comparisons.

Calculating the cost of cooling tower life cycle based on the method of calculating the total cost of purchase and maintenance is simple. However, the accuracy of purchasing this equipment depends on the accuracy of the information obtained. Anyone can estimate the cost of the cooling tower life cycle based on the data obtained. Hence, the calculations of two people for an evaluation and a design can be different. Subsequent discussions determine the basic components of a tower life cycle cost. The following sections outline the basic elements that make up the cost of a lifetime.

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