After choosing the right rooftop generator, deciding to buy, rent or get a generator financing, next comes another important question: how to install it?
Installing a rooftop generator is not an easy task. It has some rules that should be followed. So, let’s have a look at some of them.
Issues of the equipment delivery to the installation site
One of the main challenges faced by rooftop power generator installers is the issue of transporting equipment to the top of the building. In particular, heavy cranes impose certain restrictions. So a crane with a lifting capacity of 100 tons with a boom radius of 30 m is able to lift a load whose weight does not exceed 5 tons. The main problem here is not lifting vertically, but moving the weight horizontally, since in this case a large load is transferred to the crane boom. For example, to lift a 1.3 MW power generator weighing 22 tons onto the roof of the eighth floor and position it 14 meters from the edge would require a crane with a lifting capacity of 250 tons.
One of the options for solving the problem of cargo delivery by a crane and (or) insufficient free space on the ground for installing a crane is to disassemble the power generator into separate parts (engine, generator, frame, etc.), deliver them separately and final assembly is already on site installation. In general, this option, of course, takes more time, but in this case, a crane with a lower capacity will be required, and the total cost of installation work will increase slightly.
The third delivery option is the possibility of using a helicopter. Here it is necessary to take into account a large number of existing restrictions, but if they can be overcome, this option is the most cost-effective and time-efficient.
Approvals required to place the power generator on the roof
Considering that placing a diesel generator on roof often leads to a certain change in the appearance of the building, this installation option must be approved by the relevant services and local authorities.
In one case, the municipal authorities consider it impossible to change the appearance of the building, in the other they only impose restrictions on the color of the container or casing. Therefore, in order to avoid problems in the future, it’s advisable to coordinate all these issues with local authorities in advance. At the same time, depending on the terms of the contract, obtaining the appropriate permits “falls on the shoulders” of the owner of the generator or the agency involved in its installation.
Fuel supply issues
In accordance with existing regulations, a limited amount of fuel can be (stored) on the roof of a building, which is not only because of the fuel weight, but also of fire safety requirements. As a rule, the volume of stored fuel is limited to 450 liters in one tank, but in any case, it is necessary to obtain the approval of the relevant authorities for the entire fuel system.
A larger fuel tank should be located at ground level and placed in accordance with fire safety requirements. From the main tank, fuel can be pumped into a service tank located on the roof. In this case, the service tank must be equipped with a float-operated fuel level regulator to control the operation of the pump. The service tank must necessarily have an appropriately sized piping for overfill protection. The diameter of the “return” must be no less than the diameter of the main fuel supply pipe.
Air duct equipment and exhaust system issues
One of the advantages of placing the power generator on the roof is the possibility of saving on air ducts and the exhaust gas system. However, there are certain limitations here as well. In particular, if the roof is located below the level of neighboring buildings, the exhaust system must be designed taking into account the prevailing winds. In some cases, if there are offices with open windows nearby, in some cases it is recommended to use a vertical chimney with a weatherproof hood.
The air duct outlets must not contain any objects that restrict the free flow of air. In addition, the outlet of the air ducts must be directed in the opposite direction from the direction of the prevailing winds. Otherwise, there may be problems with the release of air or exhaust gasses inside the system. To solve this issue, it is recommended to install corner ventilation grilles on the outlets.
Laying electrical cables
When placing the power generator on the roof of a building, it must be taken into account that the total length of the electrical cables can increase significantly. According to the recommendations, control cabinets for power generating equipment are installed as close as possible to the input of a common power source, from which networks are distributed throughout the building, which can significantly reduce the length of their own power supply cables.