Rain comes. If you do not have a generator you are in danger.

In Italy, in September, October and November every year is the same story: The rain expected for an entire season falls in a few hours. The consequences can be devastating and vary depending on how much you are prepared for the extreme event.

How frustrating it is when you lose valuable goods and sometimes a lifetime of memories.

Being prepared for such an event means to be equipped with systems and facilities capable of preventing the accumulation of rainwater. A common example is water lift pumps, usually placed in basements and underground rooms, with the purpose of preventing flooding from rainwater or worse, of sewage seepage infiltrations. Being mainly submerged pumps, their functionning is closely related to the presence of electricity from the grid or from auxiliary sources such as generating sets.

Owning an emergency drainage system for rainwater and not having a generator set is as useless as preparing for a long and important car trip without taking care to fill the fuel before leaving. What a feeling will it be when everything does not work? Anger and frustration will be double.

What is the relevance of a flood or flood and the lack of electricity? It is simple: when there are atmospheric events that interest entire cities or regions, it concern all the infrastructures, including the electrical ones. In exceptional cases it may be the same network operator to establish the disconnection of an entire area from the rest of the network.

The moral is that without electricity electric pumps will not work and you are in danger.

Recently a Hurricane has devastated the Caribbean Sea and then crashed against Miami, USA, leaving millions of people in the dark for many days.

Only those with proper generating sets and high quality fuel loading facilities could face the emergency. By looking at the Social Network images of those who "thanked" their generating sets for the great work done during the emergency, I noticed that everyone set up images of professional generators. In other words, the most striking success stories were possible with really good generators and not the ones that you can get for 149,00 Euros at the mall.

In the picture below, just to give an idea of he difference, you can see  on the left a true generator suitable for emergency use while on the right a toy  where nothing is funny about it.

generatore vero e giocattolo

Beware, they both have the same power !!

In one of the next articles, we will explore the issue of the best generating set for housing, thus we will explain the technical characteristics of a generator set for the safety of your loved ones and your properties.

Meanwhile, let's try to understand schematically the difference between a generator suitable for operation in emergency conditions and one not suitable for this purpose.

condizioni scelta generatore

Dimensioning the generator set in accordance with the electric pump or vice versa?

Anything to do with sizing would deserve a separate article, however, a guideline can be outlined to approximately define a power.

First, it is useful to determine which loads to supply, thus, to decide whether to connect the generator to the electric pump or to the entire building including the rainwater lift system.

Choosing to supply an entire building will determine the nature of the loads, the priority and the timing.

Nature of loads : Single-phase or three-phase electrical loads.

Priority: A priority electrical load is such when it comes to an important device. Example: A refrigerator, video surveillance, water drainage.

 Timing  : Not all electrical loads work at the same time, so the required electrical power may not match the sum of all detected loads.

Regarding power, there are no great deals unless the attention to   not dimension the generator at 100% of the load. (A 5 kW electric load should not be powered with a 5 kW generator.

"Sizing" is not just the experimental calculation of the power involved, but it is also the choice of fuel tank capacity that affects the amount of hours the generator can remain in operation.

Placement of the generator:

you need to find the best position of the generator set. If you plan to mount your home-based generator in the basement, or hidden in the sight so that noise cannot disturb, you're starting off on the wrong foot.

If you do not want to hear the noise during the generator motion, you have to install a soundproofing unit (see previous article). Also, choose a generator that is aesthetically up to the environment in which it will be positioned.

Get advice from a professional about where and how to place your home-saving generator.

You'll do a safe and  productive job and you'llthank yourself for being far-sighted.


“Let’s cogenerate”! What is a "CHP", Cogeneration plant and how it works?

The world's first power plant (built in New York by Thomas Edison in 1882) was essentially a cogeneration plant because it provided electrical heat and power to Manhattan's buildings.

From a performance point of view, the generator is a machine that "sucks".

Indeed, all the generators have a poor performance because, to produce electricity, they waste enormous amounts of heat energy dispersed through the exhaust gas, the radiator and the natural irradiation of the hot parts of the engine.

cogeneratore orefice generators.jpeg

The cogeneration plant, also called CHP, allows the simultaneous production of electrical energy and thermal energy in the form of hot water or steam.

For years, cogeneration has been an exclusive technology of companies and large plants that consume huge amounts of heat, but today it’s a technology increasingly closer to small and medium-sized companies and even the private sector, due to the evolution of energy costs which has made cogeneration systems more competitive than ever before, and a technology that makes small plants more and more reliable and economically sustainable.

Most of the cogenerations operating in Europe are powered by low-cost fuels:

·        CHP plants using natural gas

·        Biogas CHP plants

·        Vegetable oil-fuelled CHP (palm oil, rapeseed oil..)

·        Syngas CHP (gas produced by pyrolysis processes)

·        Diesel CHP plants

In Europe the installations’ trend follows that of incentives, so the choice of which fuel to use is based on economic factors.

Companies that choose to produce energy with a CHP plant are those that consume large amounts of thermal and / or electrical energy, better if both.  Think of a hotel, shopping centres, sports facilities, dairies, these are just some of the major energy consumers who choose a CHP cogeneration.

The advantage of a CHP plant is not only in the cost of self-producing energy, but also in the energy independence that is achieved. The most virtuous and careful structures that we follow have chosen a triple power source: CHP plant + Emergency Generator + Electricity Grid. In this way, not only do they have a low energy cost, but they do not risk staying in the dark in the event of a CHP plant malfunction or during maintenance stops.

When is a CHP plant worthwhile?

The entrepreneur who chooses to install a CHP plant, wants to make profits by reducing costs, and has made one or all of the following evaluations.

He assessed the energy demand of his structure by doing an energy audit. In the event that electrical consumption prevails over the thermal consumption, assess whether there is a physical proximity between the CHP plant and any thermal user, bearing in mind that this must go in unison with the electrical one, while maintaining a certain flexibility, as the demand heat and electricity can be disproportionate to each other in some periods.

The actual convenience is finally assessed on the basis of the cost of energy by the supplier and the sale of the same with the introduction into the network. The advantage is certainly that of putting all the electricity that is not consumed into the grid, earning a profit.

Finally, the assessment is objectively influenced by the cost of the fuel and its purchase conditions, on which the market price fluctuates (the fuel, whatever it is, is subject to price variations) and to the possibility of deducting costs and excise taxes. .


Business Plan is not a "Fable".

When designing a cogeneration plant, the conditions that allow a return on investment within the terms set in the financial plan are to be considered.

Unfortunately,  the conditions resulting from the experimental calculations are not reflected in the real operating conditions and in general during the whole life of the CHP plant.

Even the best CHP plants stay off many hours a year for small or big problems. From direct experience in the operation of cogeneration plants we can say that a small component, even a simple temperature probe, or a sleeve is enough to force a generator to stop.

The business plan is not a fable, it is a tool to validate the financing of the bank, but it is above all the project that every entrepreneur should check and use to make further assessments on the investment time and duration of exposure that this involves. . With this we must not imply that a CHP plant is a nut to track, but only that the best of conditions is not said to be the most realistic. All this because the income statement is based on the incentives provided for the plant, therefore only costs are accumulated when the plant is stationary.

How does a CHP plant work?

Simplifying to the extreme, we can state that the CHP plant consists of two main elements, the Generator, in turn composed of engine and alternator, and one or more heat exchangers.

At a theoretical level, the exhaust gases emitted by the generator and the coolant used to cool the engine and keep the temperature constant during operation, are already potentially usable because they are available at high temperatures. In reality, obviously, it is not possible to use these fluids directly, as being contaminated they are harmful.

The exchanger is installed in such a way as to intercept the exhaust fumes, these give heat to another fluid (be it air or water or other fluids in the liquid state).

The most common exchangers are plate and tube bundle exchangers. In the first, the fluids at different temperatures exchange their thermal content through the appropriately arranged surfaces of the exchanger, the plates in fact.


Everyone who’s dealing with a generating set has for sure heard about kW and kVA and found it easier to take the kW as a unit of measurement.

Knowing the difference between watts (kW) and Va (kVA) is useful for more detailed determination of the scope of the generator set.Knowing the difference between Watt (kW) and Va (kWA) is useful to determine in greater detail the specific application of the generating set.

Orefice Generators - All rights reserved

Orefice Generators - All rights reserved

Last year during class I used a classical example but obvious to the audience to explain to my student the difference between kVA and kW: Comparing the electric power of a generator to a glass of beer.

Pouring some beer in a glass, two separate parts are formed: the beer itself and the foamy head. We can consider the glass as the maximum power, the foam as the reactive power and the beer as the real power.

“Apparently” the glass is full but what will quench our thirst is only the part of the beer not the foam. However, to drink the beer you should also drink the foam which, even though it tastes a bit bland, helps to fill out the glass first than the belly.

Just like the foam in the beer, the reactive power is to be considered even when it has no need and it is connected to the power factor which is 0,8 for the alternator of a generator.

The power factor is the ratio between the real power vector module flowing to the electrical load and the apparent power in the circuit.

Therefore, to determine the real power of a generator we just need to multiply the kVA value by 0,8 and vice versa divide by 0,8 to switch from kW to kVA:

kW = kVA * 0,8

kVA = kW / 0,8

Example: To which nominal kW does a 20kVA generator correspond? You should multiply 20 x 0,8 to obtain the real power in kW which is 16kW.

The term “apparent” also gives the idea of something that looks like but it isn’t that.

If the reactive power is almost considered as waste why then the apparent power is taking into consideration when talking about diesel generators?

This is a common question that I have always heard because, in fact, it seems not to make sense taking into consideration the apparent power when looking for the real one.

The answer is simple: The apparent power, being connected to the current value present in the circuit, is useful. It can be considered as the maximum value of real power that we can obtain by reversing the discrepancy between voltage and current.


Remember the beer example? Well, imagine you are reducing the foam quantity in the glass and refill it with other beer!

The real and apparent power values get close until they become equal when the power factor tends to be 1. This happens when the generators powers a resistive load.

For the single phase generating sets with 230V voltage, there is no discrepancy therefore, considering a power factor 1, the real power will be the only useful power to be considered.

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