Unico: a product, a motto, a standard The self-powered street lighting compatible with the other lighting systems.
Unico - photovoltaic lighting point, self-powered compatible with other lighitng systems

In recent years, there has been a renewed interest in solar-powered outdoor lighting systems. Best and inexpensive modules, more efficient and cheaper batteries, but above all LED fittings supplied in direct current (DC) mode: these are the main reasons for a growing success.

Choice of the luminaire has become an important issue, lighting fixture must make it possible to integrate direct current power supply while improving the efficiency of the system. With the introduction of LED technology, both AC fluorescent and low pressure sodium sources became outdated solutions. The market however remained in the hands of PV know-how stake holders, developing projects with good energy management systems, but lacking in lighting levels (low lighting efficiency and power-on means).

Today Reverberi Enetec is evolving its UNICO product: compliance with street lighting standards, featuring both astronomical and operating cycles.

UNICO 2.0 has been designed as an extremely efficient system, from the point of view of lighting technology, ensuring constant lighting performance with low consumption (from -20% to --50% compared to competitors). This has been possible thanks to the efficiency of a top-quality lighting fixture along with Reverberi technologies as to ensure both optimal switching-on length and fully standards compliant perfect dimming.

The lighting fixture

The lighting fixture is a primary branded LED light fixture.

The self-powered street lighting compatible with the other lighting system

System’s energy manager

This part of the system consists of:

  • Post-top mechanical support
  • PV generator
  • Trick box: composed by:
    • Management plate (charge management device, LPL/FV)
    • Battery

Post Top support

Mechanical post-top support is made of galvanized steel: one side attaches to the street pole and other side allows fixing of the PV module. Since it is fixed to the pole with two screws, our support allows SOUTH orientation of module as to maximize production. Another important aspect: the module is attached frontwards to the structure allowing both simple installation and easy adaptability to different modules available on the marked.

PV generator

UNICO system features standard photovoltaic modules within grid connected plants.
Advantages of this choice are multiple:

  • Prompt availability
  • Easy interchangeability
  • Technologically up to date models

The self-powered street lighting compatible with the other lighting system

Trick Box

Trick Box is located underneath the PF module and contains:

  • electrochemical accumulator
  • back plate charge controller and LPL/FV

Trick box degree of protection is IP22, enough to ensure optimum thermal management of battery and electronic components. Electronics are locaded into separate boxes, IP65. All components are equipped with special connectors to minimize installation time and increase, at the same time, security of connections.

Electrochemical Battery

Two AGM deep discharge 100 Ah batteries are supplied as standard, batteries may be connected either 12 or 24V keeping capacity as constant. Alternatively GEL version is provided. As a third option lithium version (LiFePO) is available. Please be aware that this solution may cause problems for charges occurring nearby zero Celsius degrees.

Charge controller

A charge controller is supplied, featuring, photovoltaic module side, a maximum power point tracking (MPPT), which lets user maximize conversion efficiency. Charge controller is self-regulating for 12 and 24V systems.

LPL/FV

LPL/FV represents the evolution of LPL management module, introduced six years ago by Reverberi and installed in tens of thousands of luminaires, with additional features for specific use within photovoltaic domain. In particular a GPS module has been integrated onboard, allowing clocks synchronization in each UNICO unit and, together with the astronomical clock, allowing better energy saving and synchronization of switching-on.
LPL/FV stand-alone version features 32 onboard cycles per hour selectable through dip-switch and 1 configurable dimming profile through PC local programming, with countless programming modes.

UNICO may be connected to a normal Reverberi Enetec Opera range tele control system, avoiding heterogeneous solutions in case of simultaneous presence of different systems working, with same technology.

Astronomical clock advantages

Optimized daylight usage and timely plants ignition represent a source of often ignored savings.

Civil Twilight is the time length where the Sun is between 6° below horizon and line of horizon. Within this timeslot plant switchingon has to be placed. Duration of “Civil Twilight” in a given location mainly depends on latitude, longitude and day of the year, as well as the rising and setting of the Sun.

Choice of the moment at which both switching on and off of the plants have to be set is affected by area’s morphology (flat land, hills or mountains) and by specific users’ needs. It is therefore a plant manager choice of 100% “exploiting” the whole twilight by placing ignition of plants either at the end of Civil Twilight or select a percentage within this same time period.

In traditional PV lighting points, ignition control systems is being managed through PV module voltage reading, acting as a twilight switch. These commands are very imprecise as they work same as twilight photocell operating mode. Only the astronomical clock can guarantee actual energysavings between 5% and 15% compared to a traditional system. It is also not guaranteed,  if there are multiple systems, simultaneous switching-on of all plants.

Twilight switch, associated with GPS, makes it possible to calculate power on and off times working on available latitude and longitude of the installation, time zone and percentage of Civil Twilight. User can also activate an adjustment allowing to add or subtract a fixed time interval to the value calculated by Astronomical twilight switch’s software.
This correction can be set independently for the four seasons of the year. In case of multiple installations, clocks synchronization ensures simultaneous ignition of all plants. All twilight astronomical switch setting, wherever a remote management is available, may be performed from a remote PC.

Dimming profiles

Typically in PV lighting points, switching on and off and hours of dimming are not based on a astronomically set time but they are working on light condition at both twilight and dawn.
In other words streetlights do not have an accurate clock onboard and they base their switching-on and any dimming from the night-time actual the condition. When the photovoltaic module’s voltage drops below a certain value, a timer managing switchingon, dimming and switching off is activated.

For example at night condition the timer switches-on lighting fixture to 100%, then after two hours drops it to 50% and so on. Time of night condition differs significantly throughout the year and therefore also dimming time schedules.

All this leads to a marked waste of energy: both because night condition is calculated incorrectly and because lighting fixture is switching-on at full power when not needed.

The self-powered street lighting compatible with the other lighting system

This is demonstrated in the example above.
It is clear that in the photocell case (i.e. switching on and off determined by PV module generated voltage) and without Astro user is forced to set a fixed switching-on time at full power starting from night condition, and this time remains static in each
season. With the Astro option instead luminaires can be switched-on at night condition and always dim, in every season, at a given time.

This allows energy savings which results or in long periods of plant working at full power at different times or saving in terms of sizing of system components (smaller) or in terms of reliability and component life (fewer depth of discharge and increased battery life for example).

At the end of the day LPL/FV is a sophisticated energy Manager available in battery, fully remotely controllable thanks to Reverberi ENETEC Opera range’s radio technology, equipped with a precise clock (as constantly synchronized by GPS) able to properly switch on and off with no waste of energy and featuring sophisticated lighting flux dimming profiles, with the goal of saving energy but according to EN13201 (UNI11248) prescriptions, then in full safety.

Performance of the luminaire

Performance of the luminaire represents one of the many particularities of UNICO 2.0.
The highest efficiency of charge management system combined with luminaire’s performance allows UNICO 2.0 to be used in applications where design parameters’ compliance to the standards is required, instead of just providing light.

Consider for example all parameters that must be respected in road applications, by category, for a road with these features:

  • Two-way lanes
  • Width 6 m
  • CIE C2 bitumen

Following parameters have been set as well:

  • Pole height 6 m
  • Center-to-center Distance 20 m
  • Outreach 0m (roadside located light fixture)
  • Single row of luminaires
  • MF = 0.8

As per EN13201 (UNI EN 13201-2), parameters to satisfy for each category are intended as follows:

The self-powered street lighting compatible with the other lighting system

Depending on luminaire’s model, following table is showing maximum lighting category where UNICO 2.0 is suitable.

The self-powered street lighting compatible with the other lighting system