- by Peter Koelewijn, 31-08-2018
The main goal of an HVAC system is to create a comfortable indoor environment. This is accomplished by treating outside air before circulating it inside. The cooling capacity of an HVAC system therefore depends on the outdoor conditions in the area. There are two properties that define the amount of heat or energy contained within the air, namely temperature and humidity. The higher both properties are, the higher the amount of energy (also known as enthalpy) which needs to be reduced in order to cool the air down. In this blog I discuss some extreme climate conditions in which ships operate that we have designed HVAC systems for.
While its long white beaches and beautiful boulevards make Fortaleza a wonderful place for a holiday, conditions can be quite challenging. Fortaleza’s close proximity to the equator gives it a more or less constant, very high temperature throughout the year. The most extreme conditions occur during northern hemisphere winter: the hottest ever measured was 34 °C with a relative humidity of 56%, resulting in an enthalpy of 85.7 kJ.
Willemstad is capital of Curacao, an island that’s part of the Kingdom of the Netherlands located off the coast of Venezuela in the southern Caribbean. Its position close to the equator means that average temperatures in Curacao are around 30 °C throughout the year. When temperatures peak at around 35 °C and the relative humidity is 53%, enthalpy is 86.7 kJ.
The city of Jeddah is located on the western coast of Saudi Arabia and is the second largest city in the kingdom. The climate is searing hot with rain vanishingly rare. Thanks to the city’s position on the shore of the Red Sea, temperatures aren’t as high as further inland, but relative humidity is that much greater. A high temperature of 36°C and relative humidity of 60% give an enthalpy peak of 98.1 kJ.
Manila is the capital city of the Philippines, an archipelago situated in the western Pacific Ocean. Manila is close to the equator, giving it a tropical climate with temperatures that range between 30 °C and 35 °C, and lots of rain throughout the year. The most extreme condition we found here was 39 °C. With a relative humidity of 57%, this gives a heat load of 109 kJ.
Abu Dhabi is a city on the Persian Gulf with a desert climate. There is almost no rain and the environment is very dry. During the hottest period between May and September, temperatures can climb as high as 36 °C; with a relative humidity of 75% the enthalpy then reaches a maximum of 114.5 kJ.
The conditions above have been measured during a certain part of the day, mostly in the evening after sunset. During daytime, the heat of the sun ensures that relative humidity isn’t as high. This means that average conditions can be considerably milder than the extremes. As a sales manager, I get a lot of requests to design systems for extreme conditions such as 47 °C with 95% relative humidity. This is a solution in search of a problem: such conditions are very rare and would often result in an excessive system that’s far too large. And oversized shoes are rarely a good fit.
Peter Koelewijn | Sales Manager
Peter Koelewijn has been working at Heinen & Hopman since 2001. Starting out as a mechanic, he gained valuable field experience mounting ducts and pipes for various shipbuilding projects. Five years later he switched to engineering, where he worked his way up from draughtsman, to engineer to site manager, leading teams of HVAC mechanics at one of the largest shipyards in Germany. The last couple of years he has been working as sales manager, combining knowledge from the field and the office to find the best solutions for our customers.