---
title: "Central Air Conditioning vs. Evaporative Air Coolers vs. Negative Pressure Fans: A Comparison of Three Ventilation and Cooling Methods"
url: https://tiercooling.com/posts/central-air-conditioning-vs-evaporative-air-coolers-vs-negative-pressure-fans-a-comparison-of-three-ventilation-and-cooling-methods/
date: 2024-02-20
modified: 2026-09-28
lang: en
author: "info@tiercooling.com"
description: "Currently, ventilation and cooling methods widely used in workshop ventilation and cooling include central air conditioning, evaporative (environmentally friendly) air coolers, and negative pressure fans. What are the differences between..."
categories:
  - "News"
word_count: 401
---

# Central Air Conditioning vs. Evaporative Air Coolers vs. Negative Pressure Fans: A Comparison of Three Ventilation and Cooling Methods

Currently, ventilation and cooling methods widely used in workshop ventilation and cooling include central air conditioning, evaporative (environmentally friendly) air coolers, and negative pressure fans. What are the differences between these three ventilation and cooling methods? Let’s hear the explanation from Run Dong Fang:

1. Central air conditioning cools via positive pressure, i.e., it introduces cold air into the space to blend with the existing hot air. Central air conditioners and cabinet air conditioners must be used in a sealed space to achieve good cooling results. The downside is poor air quality — skin contracts and loses moisture — and they cannot remove dust or relieve stuffiness, so moisture supplementation and intermittent ventilation are required. Equipment investment and operating electricity costs are also very high.

2. Evaporative air coolers can be used for ventilation and cooling in open spaces. Their drawbacks are poor cooling performance and ventilation that relies on the natural diffusion of air, though they do offer some dust removal and air-refreshing effects.

3. The ventilation and cooling principle of evaporative air coolers in a sealed space is to install negative pressure fans on one wall to forcibly exhaust hot, polluted indoor air out of the room. A water curtain wall (a special honeycomb paper with excellent moisture absorption, resistance to acid and alkali corrosion, no mildew, and many small holes for ventilation that forms a thin water film) is installed on the wall opposite the fans. Outdoor air enters the room at atmospheric pressure while being filtered by the water in the wet curtain and exchanging heat with the water film. According to general design, the indoor air can be exchanged with outdoor air two or more times per minute. This excellently solves problems of stuffiness, high temperature, odors, and dust in factory buildings. With this ventilation and cooling method, the equipment investment is generally RMB 40,000–60,000 per 1,000 square meters of factory space, with an hourly operating cost of RMB 7 (11 kW). Under normal conditions, the indoor temperature can be controlled at 26–30 degrees (combined environmental temperature). In fact, 30 degrees is not high. Even when the outdoor temperature is as high as 36 degrees, we can imagine that, like standing in the shade of a tree on a summer day with a cool breeze blowing, people will still feel very refreshed. Congratulations — the evaporative air cooler wins this contest and solves the selection dilemma!