How to select optimal generator set enclosures

When you are designing or purchasing a gen-set, the type of generator set enclosures used is an important consideration.

If it’s cold outside, you want to be able to keep heat inside the enclosure.

Maintenance access is important, especially in the winter.

Cooling system performance is important in hot climates and in the summer.

Durability, impact protection, and transportation issues are all things you must consider.

Choosing the right generator set enclosures can lead to:

• More thorough AND more frequent maintenance
• Faster and more complete service
• Overhaul procedures will be less likely to require engine removal
• Longer filter life and maintenance intervals

The types of generator set enclosures that I cover are:

• Open skidded
• Canopy
• Skin tight, sheet metal enclosures
• ISO shipping containers
• Purpose-built buildings
• Heavy duty fabricated metal enclosures

Open Skid Gen-Sets

Technically this isn’t a type of enclosure, but it is something to consider for some customers.

This design provides the least amount protection, but it is the most compact and cheapest option possible.

An open skid gen-set is a very versatile piece of industrial equipment and they are found throughout the world.

However, they tend to have the shortest operational life, due to their constant exposure to the elements.

Care must be take to ensure proper rain protection for the air filter intake and exhaust outlet.  Typically an exhaust rain cap and an air filter intake hood (mushroom hat) will do the trick.

Blowing snow, dirt, and sand will reduce air/fuel/oil filter life, will block and erode the radiator cooling package, reduce your ability to extend service intervals, and can affect alternator longevity.

The possibility of high moisture  (humidity and rain) can negatively affect your alternator, especially when the unit is not in use.

There are definitely some benefits to use an open skid-mounted generator though.

The most obvious is maintenance and service; no piece of equipment is easier to service than an open gen-set.

Another is the compact size.  For a given electrical output, this is the smallest footprint you can achieve.

Finally, cooling the unit is much easier when it isn’t enclosed. Here you have ample access to the ambient air and don’t have to fight enclosure restriction or the engine pre-heating the air on it’s way to the cooling package.

Canopy covers

To me, this looks like a car port for your gen-set.

With this option you start with a open-skidded unit, add a leg at each corner, and then attach a peaked metal roof overtop the generator.

This does give you protection from direct rain and snow, but doesn’t prevent all of the problems discussed above.

Also, you have some protection from falling debris, tools, or lifting chains & slings.

Canopy covers don’t really affect cooling or sound attenuation much.

Service and maintenance are hardly affected unless you are removing heavier components (cylinder head, alternator, cooling package) this would require a chain fall, overhead crane, or forklift.

Again, this technically isn’t a type of enclosure, but worth considering in the correct circumstances.

Skin Tight Generator Set Enclosures

This is by far the most popular of the generator set enclosures that I will cover here.

You will see a skin tight enclosure on emergency standby, skidded prime power, trailer mounted, and compact sound attenuated gen-sets.

Here you receive more protection from the elements, more impact protection, and you can definitely add a level of sound attenuation to these units.

Skin tight generator set enclosures are the cheapest way to enclose and sound attenuate your generator and yield a small footprint.

However, if size is less of an issue than performance, then some of the more premium designs below are worth considering.

This is one concern when using skin tight enclosures and sub based fuel tanks (tanks below the generator set).

You can achieve a very small footprint with such a configuration, but the only way to increase your running time between refuelling, you have to increase height.

If you are running a prime powered generator and don’t want to have a fuel truck visiting you every 8 hours, you must increase your fuel tank size.

This isn’t a problem (other than shipping) until maintenance has to be performed from a step-ladder.  At that point there are safety precautions and considerations that have to be made.

ISO Shipping Containers

If you work in a net-importer country (i.e. anywhere outside of China or India), then you have an ample supply of one-trip or used ISO shipping containers.

A generator-set packager or end customer can purchase a unit directly and modify themselves.

However, around major port locations, there are dealers who purchase ISO containers and will modify to suit your requirements.

You can add windows, doors, insulation, air inlets/oulets, hoods, etc. to meet your needs.

These are very versatile and modular enclosures for your generator sets

Using ISO shipping containers for generator set enclosures is the cheapest way to achieve some heavy duty impact protection, cold weather performance, and sound attenuation.

For internal & external dimensions and more information please visit my ISO Shipping Container Specifications page.

Also, you could visit the wikipedia page.

Purpose-Built Buildings

These are common sights in resource-based industries such as oil production, natural gas compression, power generation, and mining & minerals.

Manufacturers of purpose built buildings will build directly from your drawings, adding doors, windows, and other inlets as you require.

One major advantage of these buildings over ISO containers is the ability to increase the width of the end product.  This allows you to better space out the equipment housed inside.

However, they tend to be less heavy duty and more susceptible to impact damage.

Though they can be skid mounted, they tend to be less portable than the other solutions presented here.

However if you require fully customized generator set enclosures, this is a more economical option to the custom fabricated option below.

Fabricated Metal Generator Set Enclosures

The most premium generator set enclosures are custom built in a metal fabrication shop.

These combine the heavy-duty construction of an ISO shipping container, with the customizability of a purpose built building.

Typically skid mounted and designed for use in extreme cold environments, these are preferred by oil, gas, and mining service companies.

Many of these premium units contain two identical gen-sets.  Depending on your circumstances, you can either parallel these units or use them as mutual backups for redundancy.

Paralleling will allow you to run just one unit when load levels are low.  The second unit will be automatically started and brought on line when load levels increase.

However, this is an expensive option and not always recommended for units below 150kWe.

Instead the second unit can be used to backup the first.  A manual transfer switch is used to select with generator is supplying power to the distribution.

Some of the custom features you can include in your enclosure design:

• Air intake louvers – keep closed when unit is off, being transported, or cold and being idled.
• Double-walled fuel tanks – can be inside, but outside behind the enclosure is more economical
• Light tower masts or area lighting – you have a generator, a custom enclosure, and a custom skid – when not reduce the expense of purchasing a light tower too
• Air intake hoods – to help keep rain and snow out of the building
• Exhaust air hoods  – direct you radiator exhaust air away from people or buildings.  An easy way to reduce your noise levels
• Radiator cooling package shutter stats – open at a preset coolant temperature preventing fan air flow when the engine is cold
• All of your electrical distribution

We hope this discussion of generator set enclosures has been helpful to you.

As always, please comment below with your own experiences or questions.

We could talk at length about this topic since selecting the proper generator set enclosures has always been a major factor in customer satisfaction.

If you have a case-study project to share with others on here, we will work with you to select an enclosure & vendor and then present in a later post on this blog.

If your project is more confidential, please visit our generator set services consulting page.