This is the most basic version of the generator set. It is mainly used in indoor installations that already have a technical room designed with sound insulation, forced ventilation and its own safety measures. It consists of mounting the engine, alternator and auxiliary elements directly on a structural metal base.

Its advantages include full access for maintenance, lower acquisition cost and better natural heat dissipation. Its disadvantages include high noise levels and direct exposure to dust and other contaminants. The unencased version is recommended for industrial installations, controlled enclosed environments and projects that integrate customised encapsulation solutions.

This configuration incorporates a metal enclosure designed to significantly reduce the noise level emitted by the generator. The bodywork usually includes laminated steel panels with acoustic insulation, acoustic panels, acoustic grilles for air intake/exhaust and exhaust silencers. The entire system is protected and certified for outdoor use yet remains compact and easy to transport. 

In terms of advantages, the noise level is controlled and adapts according to power; for example, the most basic version of the HGY Series container is below 80 dB(A) at 1 m. In addition, it is protected against the elements and quick to install. As for the disadvantages, access for maintenance is limited, air flow must be ensured for cooling, and it is more expensive than the Open Skid model. 

Containerised generator sets are housed inside an industrial container, usually 20' or 40', adapted with structural reinforcements, thermal and acoustic insulation, forced ventilation, fire extinguishing systems and secure access. This format protects the generator in extreme environmental conditions and facilitates transport, storage and stacking.

One of its main advantages is that it is a robust all-in-one solution, as well as being compatible with maritime and land logistics, and offering greater protection against external agents. Its disadvantages are its greater weight and volume, higher manufacturing cost, and specific foundation and crane requirements for installation. The containerised system is used for critical applications, isolated or climatically hostile areas, large-scale industrial projects, mining and oil & gas.

The correct configuration must be selected based on a technical analysis of the operating environment, the project objectives and local regulatory requirements. There is no single valid solution: each option responds to a specific application profile.

In addition, the output voltage level must be defined according to the electrical distribution system: low voltage for commercial or residential installations and medium voltage for industrial networks or parallel generation to the grid.

To mitigate these noise levels, the use of industrial silencers is recommended, which can reduce noise by up to 20-25 dB(A); while -35dB(A) for residential use and -40dB(A) and above is critical.

Technical rooms must incorporate absorbent coatings, acoustic traps in air ducts and sealing of structural joints. Regarding enclosed configurations, the canopy must comply with acoustic certifications and ensure proper sealing.

When the generator is installed in enclosed spaces, such as technical rooms, engine rooms or substations, it is essential to design a comprehensive solution that guarantees a safe and thermally stable operating environment. In this type of application, forced ventilation must be carefully dimensioned to ensure the continuous extraction of heat generated by the engine and alternator, preventing any recirculation of hot air within the enclosure.

The thermal management strategy must include accurate air flow calculations, evaluation of static pressure in ducts, selection of grilles with appropriate flow coefficients, and the integration of acoustic silencing solutions that do not compromise the necessary flow rate.

The installation of thermal sensors strategically distributed within the room is recommended to activate auxiliary extraction systems in the event of sudden temperature increases or failures in the main system. When considered from the design phase, these solutions make it possible to transform a closed room into a controlled and reliable environment for the continuous operation of the generator set.

The back pressure generated in the exhaust system is a critical variable that directly affects engine performance and durability. The calculation must consider all intermediate elements:

Where each section contributes to a pressure drop associated with length, diameter, internal roughness, and number of bends or restrictions. The maximum allowable back pressure in the exhaust system is a critical parameter determined by the engine manufacturer and must be strictly adhered to during the design and execution phases of the project.

This residual pressure, generated by resistance to the passage of combustion gases through ducts, elbows, silencers and external outlets, has a direct impact on engine efficiency. If not properly controlled, it can cause thermal overload in internal components due to the difficulty of heat evacuation, increased pollutant emissions by altering the quality of combustion, and a decrease in volumetric efficiency by hindering the entry of clean air in successive cycles.

The chimney design must include cleaning registers, thermal insulation, anti-vibration fixings and, in cold areas, anti-condensation and drainage devices. Complying with the manufacturer's specifications regarding back pressure not only ensures optimal performance of the generator set but also extends the life of the engine and prevents premature failure of critical exhaust system components.

The fuel system is a fundamental component in the architecture of a power plant, as it determines both operational autonomy and the overall reliability of the facility. Its design must meet hydraulic, regulatory and operational criteria.

The supply system must ensure autonomy and operational continuity under any grid failure scenario. It therefore includes:

• Main tanks designed to hold the fuel required according to the load profile (base + peaks).
• Intermediate or daily tanks, located between the main tank and the engine, to regulate pressure, reduce contaminants and facilitate maintenance. This is important in case the engine pump is unable to draw fuel from the main tank. 
• Automatic transfer systems using pumps, valves and level sensors.

The condition of stored fuel is a critical issue. Over time, diesel fuel can degrade, generating sediment, bacteria, emulsified water and corrosive acids. These contaminants affect the injection pump, injectors and the combustion system in general. Therefore, it is recommended that fuel be rotated at least twice a year and, in the case of low consumption, that a maintenance plan be implemented that includes periodic filtering, water separation, biocide treatment, and quality analysis.

An additional good practice is to incorporate level, pressure and temperature sensors into the fuel system, connected to the group's control system (digital controllers), which allows continuous monitoring of the system's status and prevents failures due to lack of supply or abnormal conditions.

The calculation of fuel volume should consider:

• Nominal hourly consumption.
• Expected duration of operation without mains power.
• Refuelling logistics and frequency.

Stored fuel should be kept in optimal condition with a minimum rotation of twice a year and the implementation of conditioning systems with filtering, water separation and antibacterial additives. 

Electrical safety requires a robust grounding system with low impedance that is capable of evacuating fault currents without affecting people or equipment. The recommended standard for non-critical applications such as hospitals is the TN-S scheme, in accordance with IEC 60364-5-54.

The configuration must include:

• Spike, ring, mesh or plate electrodes, depending on the resistivity of the ground.
• Bare copper conductors or conductors with green/yellow insulation.
• Corrosion protection and access to measurement points.

The installer is responsible for validating the design through resistance measurements, continuity tests and documentation in accordance with local regulations.

"To ensure the safety of people in the event of indirect contact with live elements, earth fault protection relays, also known in Spain as differential relays, are installed. This relay must be adjustable in terms of time and sensitivity. The standard specifies immediate tripping of the protections in the event of a 30mA fault current for standard installations" , asegura Pablo Zárate Fraga, Sales Engineering Manager at HIMOINSA. 

The design of the ventilation system in a power plant is an essential part of the technical project, as it largely determines the thermal stability of the generator, the protection of the components and the overall efficiency of the system. During the operation of a generator set, a significant portion of the energy generated by the engine is converted into heat, which must be evacuated in a controlled manner to prevent overheating, shutdowns due to high temperatures, or premature deterioration of materials.

Unlike systems with natural ventilation or simple extraction, generators require an engineering approach based on forced convection heat transfer, directed flow, energy balance and appropriate selection of openings, grilles and flow rates. The cooling air must travel the entire length of the engine and alternator, absorb the radiated heat, and exit without generating internal turbulence or recirculation.

Heat transfer by forced convection requires adequate air inlet and outlet sections. The minimum surface area must be:

The design formula:

The ventilation system must be designed considering the complete thermal balance of the unit:

• Combustion heat output.
• Residual heat on metal surfaces.
• Heat exchanger efficiency.

This analysis allows the selection of suitable extractors, grilles and auxiliary fans to dissipate heat under different loads.

There are two main strategies for cooling solutions:

• Integrated radiator: located on the generator itself, with a fan coupled to the motor. This standard solution is for most generator sets, if space and the environment allow it.
• Remote radiator: there are thermal restrictions in the room and, therefore, the aim is to reduce the noise level. It is possible to locate the radiator away from the generator.

There are two possible configurations:

• Isolated system: incorporates a heat exchanger that separates two independent circuits with an auxiliary pump.
• Non-isolated system: if there is only one circuit, a second pump should not be installed in line with the engine pump.

The intake air entering the engine must be kept at an optimum temperature to ensure efficient combustion and stable dynamic response. During the turbocharger compression process, the air temperature increases significantly, reducing its density. Cooling this air before it enters the cylinders allows a greater mass of oxygen to be introduced, which improves the power generated and reduces pollutant emissions. To do this, specific aftercooling systems adapted to each power plant configuration are used.

• Charge Air Cooling (CAC): uses an air-to-air radiator. Only compatible with direct installation. Not suitable for remote radiators.
• LTA (Low Temperature Aftercooler): air-to-liquid exchanger integrated into the engine. Allows for remote systems. Offers greater thermal stability under dynamic loads and better transient response.

Physical verification of the useful sections of air intake and exhaust, exhaust lines and fuel supply, ensuring that they comply with the dimensions, routes and materials specified in the project.

Confirmation that the cooling system operates within the engine manufacturer's nominal thermal range under different loads.

Checking for the absence of hot air recirculation in the enclosure by measuring the temperature at key points in the flow.

Performing electrical tests: continuity of protective conductors (PE), insulation resistance, verification of the correct connection of the neutral and earthing according to the TN-S scheme.

Review of control and protection systems, including the correct operation of alarms, thermal sensors, fuel level, oil pressure and voltages.

Functional testing with real load or resistive load bank, simulating operating conditions to validate frequency stability, voltage, automatic voltage regulation (AVR), transient response and thermal performance.

Evaluation of operating noise level (dB(A) at 1 m and 7 m), comparing it with the planned acoustic design.

Verification that the structural elements and anchors of the unit are correctly installed: silent blocks, levelled bases, anti-vibration mounts and absence of displacement.

Review of auxiliary systems, such as engine block heaters, battery chargers, autonomous ventilation systems, room lighting and fire protection.

Having a high-quality generator alone does not guarantee the success of an installation. The determining factor is how the various subsystems that surround it are integrated: ventilation, exhaust, fuel, control and grounding. These elements are not accessories, but structural axes that directly condition the performance, durability and safety of the entire system.

The difference between an operational and a professional installation lies in the technical detail applied to each design decision, in the anticipation of critical scenarios and in the ability to align each component with the highest standards in the sector. A power plant is not installed: it is built, calibrated and validated as a cohesive technical ecosystem at the service of energy continuity.