Evaporative cooling takes advantage of the potential of the outside air in dry climates to absorb moisture, which results in a temperature reduction of the air stream. But one of the major drawbacks is the continuous scale built up on condenser tubes which makes a barrier between tubes and water sprayed on them, which in turn drastically reduces the heat transfer. This results in a loss of plant efficiency and increases annual refrigeration costs as the compressor work increases for compensating the pressure drop due to scaling.
In HVAC around 27% of worldwide energy is consumed only for different HVAC applications. This project mainly focuses on this problem statement, if the scale is 0.06mm then condenser performance decreases by 16%. A mainly evaporative condenser is used in different HVAC applications.
In order to overcome this problem, regular maintenance of the condenser should be done by descaling the coils. Various descaling methods are being used in industries descaling like mechanical descaling, chemical descaling, etc. But manual descaling is preferred over other methods due to its simplicity, less cost, and reliability. Yet there are some problems in manual descaling like the number of rows of condensing tubes is very large in numbers and also the pitch between them is less so it becomes very difficult to reach the deep portion of the evaporative condenser in order to clean them thoroughly and effectively scale removal.
Table of Contents
1 Introduction
1.1 Need of Project
1.2 Objectives
1.3 Scope
1.4 Problem statement
1.5 Methodology
2 Literature Survey
3 Basic of refrigeration and air conditioning
4 Factors affecting condenser capacity
5 Classification of condenser
5.1 Air cooled condenser
5.1.1 Natural convection air cooled condenser
5.1.2 Forced convection air cooled condenser
5.2 Water cooled condenser
5.2.1 Tube in tube condenser
5.2.2 Shell and coil condenser
5.2.3 Shell and tube condenser
5.3 Evaporative condenser
6 Configuration type
7 Water distribution system
8 Fan system
8.1 Induced draft
8.2 Forced draft
9 Fouling factor
10 Scaling
10.1 How it occurs
10.2 Types of scaling
10.3 Adverse effect of scaling
10.4 How to prevent scaling
10.5 Types of descaling
11 The water quality
11.1 Water quality guidelines
12 Design philosophy and principle of operation
12.1 Design calculation
13 Cad modeling
14 Results & Discussion
15 Observation
16 Requirement of industry
16.1 Descaling cost analysis
16.2 Descaling cost
17 Conclusion
18 Reference
Objectives & Core Topics
This thesis focuses on the mechanical engineering challenge posed by scale accumulation in evaporative condensers. The primary objective is to redesign the condenser coil arrangement to facilitate easier manual descaling, thereby reducing maintenance downtime, restoring optimal heat transfer efficiency, and lowering annual plant operating costs by minimizing compressor workload.
- Theoretical analysis of evaporative cooling and refrigeration cycles.
- Evaluation of scaling mechanisms and existing descaling methodologies.
- Computational Aided Design (CAD) of a modified condenser coil structure.
- Thermal performance analysis and comparative study of standard vs. redesigned models.
- Economic analysis of manual versus chemical descaling processes.
Excerpt from the Dissertation
13. Cad modelling
In traditional design the pitch distance between condenser coils remains very less but for the purpose of effective manual descaling, the whole assembly is split into two halves and also the distance between tubes is increased so that it will be easy to reach in distant places of condenser coils and clean them easily and effectively. As this arrangement will surely facilitates manual descaling on regular basis so scale built up would be possibly less and the heat transfer rate will be in the optimal range in order to get maximum possible heat rejection capacity. Also as the pitch between condenser coils is increased the resistance to air flow becomes less so less HP fans can be used. Regular descaling will results in less pressure drop and compressor will not have to work more thus reducing the power consumption.
Summary of Key Chapters
1 Introduction: Provides a comprehensive overview of evaporative cooling, identifies the problem of continuous scale buildup, and sets the specific design objectives for the project.
5 Classification of condenser: Categorizes various condenser types including air-cooled, water-cooled, and evaporative condensers to understand their respective operational contexts.
10 Scaling: Explains the physical and chemical processes behind scale formation, its negative impact on heat transfer efficiency, and current removal techniques like mechanical and chemical cleaning.
12 Design philosophy and principle of operation: Details the theoretical design principles adopted, including the thermodynamic calculations required to maintain capacity under the new, modified configuration.
13 Cad modeling: Describes the structural modifications, such as splitting the assembly and increasing tube pitch, to enable effective and ergonomic manual descaling.
14 Results & Discussion: Compares the performance data of the project design against standard industrial units to validate the efficiency and effectiveness of the modified setup.
16 Requirement of industry: Analyzes the economic variables, specifically comparing the annual costs of chemical maintenance versus manual labor based on the proposed structural changes.
Key Keywords
Evaporative Condenser, Manual Descaling, Refrigeration, HVAC, Scaling, Heat Transfer, Coil Arrangement, Thermal Performance, Compressor Efficiency, CAD Modeling, Maintenance, Water Quality, Energy Consumption
Frequently Asked Questions
What is the core focus of this dissertation?
The research is dedicated to designing an evaporative condenser that allows for easy manual descaling to maintain high thermal efficiency in HVAC systems.
What are the central themes of the work?
The study centers on heat transfer optimization, the physical chemistry of scale formation, and the economic benefits of redesigning mechanical components for better maintainability.
What is the primary objective of this project?
The goal is to increase the spacing between condenser tubes through a split-assembly design, allowing for effective manual descaling to prevent efficiency losses associated with scaling.
Which scientific methods are applied here?
The research utilizes literature surveys, thermodynamic mathematical modeling, CAD simulation, and financial cost-benefit analysis.
What does the main body cover?
The main part of the document covers the theoretical basics of refrigeration, the classification of condenser types, the science behind water scaling, the proposed structural modifications, and the resulting thermal performance comparisons.
Which keywords characterize this work?
Key terms include Evaporative Condenser, Manual Descaling, HVAC, Thermal Efficiency, and CAD Modeling.
How does the proposed split-assembly design affect airflow?
By increasing the pitch between condenser tubes, the resistance to airflow decreases, potentially allowing the use of lower horsepower fan systems.
What is the main finding regarding cost savings?
The research demonstrates that replacing chemical descaling with a manual, accessible design can lead to approximately 83% cost savings in maintenance, while additionally reducing overall annual energy consumption costs.
- Quote paper
- Vishal Sawale (Author), 2018, Design of Evaporative Condenser with Arrangement for Easy Manual Descaling, Munich, GRIN Verlag, https://www.grin.com/document/1289700
