Danfoss Vineyards Frost Protection User Guide
- June 2, 2024
- Danfoss
Table of Contents
Danfoss Vineyards Frost Protection
Solve the challenge of vine growers with an Electric Heating system
Electric Heating by Danfoss is a symbiosis of long history formed by 2 brands
DEVI and Danfoss united under 1 company umbrella.
It derives from DEVI brand that was established in Copenhagen, Denmark, in
1942. As from January 1st 2003 DEVI has become a part of the Danfoss Group –
Denmark’s largest industrial Group.
Danfoss is one of the world’s leading companies within heating, cooling and air conditioning. The Danfoss Group has more than 23.000 employees and serves customers in more than 100 countries. The development of electric heating systems takes place in Denmark, where the head office is situated while heating elements (cables and mats) are manufactured by Danfoss in EU.
Electric Heating is an energy-efficient system using electric heating
cables to protect vines against frost damage
This design guide presents our recommendations for design and installation of
Vineyards Frost Protection system. It provides guidance for a heating cable
layout, electric data and system configurations.
Following our recommendations will ensure energy efficient, reliable and
maintenance free solution for constant wattage heating cables with 20 year
warranty.
Application overview
Every year vine growers from different regions face a problem of late frosts.
They often happen in April – May when buds start blossoming.Late spring frosts
are one of the greatest challenges vine growers are facing. Non-heated vines
can suffer considerable inflorescence damages (up to 50%), whilst heated vines
will have dramatically improved protection of harvest loss or damage and
reduce the losses to approximately 13-20%.
Worldwide, the grape and wine industry rely on three main alternatives for
frost protection: frost fans, sprinklers, and candles.
Electric Heating solves the challenge with energy efficient systems using
Electric Heating cables to protect vines against frost damage.
A green (without CO2 emissions) and sustainable lifetime solution.
Highly economic due to low energy consumption during the frosts period.
- Protected against chemical fertilizers;
- Extremely-high pulling strength (special tractors coward the vineyards, while knocking the fruits);
- Accurate power design (W) according to requested needs;
- 5 or 20 years warranty.
Heating system can provide frost protection ONLY in spring season when the bud grows and NOT in wintertime!
Benefits
- An energy-efficient solution with electric heating cables.
- Easy, fast and reliable installation.
- A customized approach to meet client’s needs, area of vinery and number of rows.
- Proven high saving compared to the existing methods.
- A sustainable solution for a green and clean future through low energy consumption during the frost period.
- Tough cable outer sheath (resistant to weather and UV)
System description
Electric Heating solves the challenge with energy efficient systems using
Electric Heating cables to protect vines against spring frost damage.
The heating cables by Danfoss are installed and fixed on metal wire along the
grapes. The system is controlled automatically by temperature sensors
connected to the controller.
Non-heated vines can suffer considerable inflorescence (bud) losses. Number of
berries can decrease by 3 times or completely disappear!
Different grape varieties can withstand frosts different.
A dormant bud is reasonably frost hardy, it can survive frost down to -3,5 °С
(Pinot Noir).
As the bud grows the water contents raise in the bud and it becomes more
susceptible to frost -1,1 °С can damage it (Pinot Noir).
We offer an energy-efficient solution with our electric heating cables for
frost protection of the vines.
The concept involves installation of heating cable along the main trellising wire of grapevines.
- Frosts protection in spring time (from 2 up to 7 days)
- The ambient temperature is -2…-8 °С
- Most susceptible to frost vineyards are located in the lowlands/valleys (low area of land)
Depending on heating level, vintage losses may be decreased
Common view of electric heating system for vineyards
System design
Following pages provide an easy design guide for selection of a Vineyards
frost protection system.
The recommendations are provided relates to heating cables, as well as
thermostats and accessories.
Heat loss calculation
Linear output of a heating cable (W/m), which is installed for main vine branch, should be at least the same as heat loss (Q, W/m).
In order to calculate heat losses and design the system, we need to know:
- Minimum ambient temperature in spring frost period (-2…-8 °С);
- Grape sort. For different sorts we need to maintain different temperature (+1…+5 °С). The temperature must be checked with vineyard owner and specified for the project calculation;
- Length and numbers of vineyard rows;
- Available total load on site, kW;
- Voltage (230, 400 V).
For medium weather conditions*, in order to increase temperature by 1 °С needs power of approx. 1 Watt.
In average can be installed from 10 up to 20 W/m for each main branch of grapevine.
Example.
Location is France and ambient temperature during frosts period is -8 °С.
Grape sort is Pinot Noir and we can maintain +2 °С near the main vine branch.
According to the data above:
Medium conditions are the following: wind velocity is from 4-6 m/s. But it always depends on local weather conditions!
System output
The heat required for vineyards frost protection depends on the following main
factors:
- Weather conditions (min. temperature, wind speed, humidity, altitude);
- Electrical data (voltage, power, control requirements);
- System performance expectations;
- Safety factor.
With data from previous example will calculate linear output of heating cable:
However, in some locations the wind is present at any time of the day. I such
cases we need to add influences of wind velocity.
Heat transfer coefficient should be considered according to wind velocity.
Safety factor is very important and depends on the following parameters:
- Tolerance of heating cable resistance: +10%…-5%;
- Cable length tolerance: +2%…-2%;
- Supply voltage: +5%…-5%.
Totally can be up to 30%
Average values of linier outputs depending on different wind velocity:
Wind velocity| 2 m/s| 3 m/s| 4 m/s| 5 m/s| 6
m/s
---|---|---|---|---|---
**Linear output***| 10,2 W/m| 11,4 W/m| 14 W/m| 16,6 W/m| 19,2 W/m
Note that values in the table above are calculated without influence of altitude, Nusselt and Prandtl criterions. For more info: [email protected]
Total system output depends on numbers and length of vine rows and should be calculated in order to choose appropriate load equipment.
Product selection
This section will show how to choose the correct heating element, control device and what accessories to use for the installation.
The electric heating system product portfolio for the Vineyards Frost protection consists of three major components:
- Heating element – heating cable with constant wattage ready-made units or drum goods;
- Controller with a temperature sensor or a controller with both temperature and moisture sensors;
- Fixing elements and accessories.
Danfoss frost protection systems can be fully automated which eliminates the
need for field personnel during frost events.
Also, the prefabricated cold connections in Danfoss factories offer
considerable time savings in the deployment of frost protection systems.
Connection to the electrical cabinet is pretty easy due to DIN rail
construction.
Heating cable selection
Most of cables are manufactured as ready-made heating elements with a specific length, with connecting power supply cable (cold lead or cold tail) and sealed joints (connection muffs or end terminals).
It is also possible to choose special drum goods which can be customized for the specific project.
Ready-made heating cables
The heating cable offered for the application is constant wattage cable with
an extremely high-quality. Its round profile and robust construction ensures a
fast, simple and safe installation in multiple applications.
Main rules how to choose suitable heating cable:
- Calculate heat loss;
- Add safety factor to heat loss (usually + 30% or 1,3);
- Outer sheath of heating cable MUST be UV protected;
- Check voltage supply and choose suitable heating cable: 230 V or 400 V;
- Choose product type: ready-made units or drum goods (usually depends on specific row length and linear output).
Range of the heating cables linear output for vineyards frost protection is usually between 10 and 20 W/m (Watt per linear meter).
Product
| Linear output, W/m| ****
Type
| Max. permissible use temp., °C| Cable dimensions, mm| Conductor insulation| ****
Outer sheath
| ****
Cold lead
| ****
IP class
---|---|---|---|---|---|---|---|---
ECsafe 20T| 20| Twin conductor| 60| 6,9| XLPE| PVC
UV protected
| One
2,3 m DTCL
| IPX7
ECsnow 20T| 20| Twin conductor| 70| 7| FEP| PVC
UV protected
| One
2,3 m DTCL
| IPX7
Thermostats/controllers
Thermostats and controllers are fitted with a complete set of control
functions for frost protection systems. It is a combination of multi
functionality and temperature control.
The product range of controls is designed for frost protection systems
including the following:
- simple electronic thermostats;
- digital controllers.
Line of simple electronic thermostats to be installed in electric cabinets with DIN rail attachment. To measure and control the desired temperature either a wire sensor (in the set) or an external indoor/outdoor air sensor must be used. The thermostat must be installed via an all-pole disconnection switch. It has a LED indicating showing standby (green light) and heating (red light) periods.
To control simple or low output (less than 3000 Watts) systems, simple
thermostats are recommended as a standard solution.
ECtemp 330 (+5…+45 °C) and ECtemp 330 (-10…+10 °C) can be used for such
purposes.
Wire sensors should be installed according to specific project data. Minimum
one sensor must be used for one heated zone (could be one vineyard row or few
rows depending on field size and location). Always contact local sales
representative or [email protected] in order to get technical help.
Find basic thermostat connections below.
For more connection schemes please contact [email protected].
Line of digital controllers have special functions which can be programmed for
different purposes.
The ECL Comfort 310 is an electronic weather-compensated temperature
controller. The weather-compensated heating system increases the comfort level
and saves energy.
Main functions and benefits:
- Easy installation;
- Optimized performance;
- Easy modifications;
- Alarm function;
- Different configurations;
- 24/7 overview of the systemж
- Ability to make log of the individual sensors
- Remote control;
- For mounting on wall and DIN rail.
Interface example:
Product| Resistive load, at 230V, Amps| Sensor type|
Temperature range, °С| Hysteresis, °С| BMS| IP class|
Installation
---|---|---|---|---|---|---|---
ECtemp 330 (-10…+10 °С)| 16| Wire| -10…+10| ±0,2| No| IP20| DIN rail
ECtemp 330 (+5…+45 °С)| 16| Wire/Air optional| +5…+45| ±0,2| No| IP20| DIN
rail
ECL Comfort 310| 4 (2 x CO and 2 x NC)| Wire| -50…+200| | Yes| | On wall
Accessories
Danfoss range has all necessary accessories for fixing, measurement and
connection in order to provide full project specification.
In order to find all accessories please refer to Product Catalogue or visit
www.devi.com.
Cable ties| Wire sensors| Air sensor| Plastic conduit
pipe| DTCL Cold leads
---|---|---|---|---
| | | | **
Plastic ties for fixing heating cables.| Wire sensors for different
temperature range.| Outdoor air sensor with IP44| Plastic conduit pipe for
wire sensors| Different cold leads with different cross sections and
construction are available for ordering
End termination repair set| Heating cable to cold lead repair
set| Heating cable to heating cable repair set| Heating cable to
cold lead/ heating cable repair set|
**| | | ****
DEVIcrimp™ CS-2C assembly kit dk 2-cond.| DEVIcrimp™ for DEVIsnow™|
DEVIcrimp™ ass/repair kit 2-cond. CS-2A/CS-2B| Repair kit cables 2 cond.
Concrete/støbesæt
Note: always use only authorized accessories!
For more details please use Product Catalogue or
[email protected].
Installation guide
After product selection proper installation should be done. Always use the
following rules during the installation process:
- Heating cable should be installed on metal wire near the main branch of grapevines, the closer the cable is to the buds the more heat it will exert on the buds;
- One cable line for one row of vineyard. All cables should be connected in parallel;
- Heating cable can be fixed by plastic ties;
- Distance between cable and vines branch is maximum 0-4 cm;
- Control system should have temperature sensors (wire sensors);
- Install sensors where the temperature is estimated to be representative for the whole installation, where 2 sensors are needed for the thermostat/controller please install at the estimated extreme points (coldest and hottest);
- Wire sensors should be installed in plastic conduit pipe (avoid direct contact of sun rays) near the main branch of grapevines;
- Alarm should be installed in order to check all cables which can be damaged by grape secateurs, tractors, etc.
-
Fix one line of the heating cable to metal wire by plastic ties.
-
Heating cables should be connected to thermostat/controller according to local norms and regulations.
Contact [email protected] for all technical information about connections. -
Install wire sensor in plastic conduit pipe and place it in coldest place near main branch of grapevines.
-
It is strongly recommended to install alarm system in order to check the integrity of the cables in real-time and before the frost season
As a result you will get reliable frost protection heating system providing a stable harvest.
Safety instruction
Heating cables must always be installed according to local regulations and
wiring rules as well as the guidelines in this installation manual.
De-energize all power circuits before installation and service.
Residual current device (RCD) protection is required.RCD trip rating is max.30
mA.
The screen from each heating cable must be connected to earthing terminal in
accordance with local electricity regulations.
Heating cables must be connected via a switch providing all pole
disconnection.
The heating cable must be equipped with a correctly sized fuse or circuit
breaker according to local regulations.
Never exceed the maximum heat density (W/m or W/m²) for the actual
application.
It is strongly recommended to use the heating cable together with an
appropriate thermostat to secure against overheating.
The presence of a heating cable must be made evident by affixing caution signs in the fuse box and in the distribution board or markings at the power connection fittings and/or frequently along the circuit line where clearly visible (tracing) must be stated in any electrical documentation following the installation.
DO’s
- For installation of cable and thermostat/controller, always refer to the local regulations/legislations and respective manuals;
- Remember to fill out the warranty certificate with the required information as this will not be valid otherwise;
- Carefully complete the installation, the cable can break when overloaded;
- If any doubt arises consult you manual or local Danfoss department;
- Ensure that the cable is sufficiently fixed and mounted according to the manual;
- Ensure that warning labels and stickers (potentially tape) with warning text is used to inform about the heat traced cable;
- Install sensors where the temperature is estimated to be representative for the whole installation, where 2 sensors are needed for the thermostat/controller please install at the estimated extreme points (coldest and hottest);
- To get the best performance of the system and avoid failures it is necessary to follow the installation descriptions;
- To get the best performance of the system it is strictly necessary to calculate the correct heat losses. Using this knowledge the cable with right output can be chosen;
- Plan every installation step and fixing point of the frost protection system ahead of time and ensure that the “run” is proper and possible;
- Ensure sensors are connected according to the applicable installation guide and/or application guide.
DON’Ts
- Never make an installation without thermostat/controller;
- Never install cables where the heat can’t be dissipated, even with a self-limiting cable the output will never become zero and the cable can overheat;
- Never let unauthorized personnel install controllers/thermostats or heating elements;
- Never use unauthorized accessories;
- Never use our products (cables, controllers, sensors, etc.) outside provided temperature range.
Case stories
https://devi.danfoss.com/en/case-stories/?page=1
Technical support
The Electric Heating team is offering valuable support to professionals when it comes to preparing your new projects.
- Recommendations for the installation and operation of the system;
- Technical trainings.
We offer support for:
- Calculation of Electric Heating system;
- Development of drawings for projects;
- Preparation of the BoM (Bill of Material);
In order to clarify the project data for different applications use the
following technical request forms, fill in with your specifications and send
it to: [email protected]
https://devi.danfoss.com/en/support/
Danfoss A/S
Climate Solutions danfoss.com +45 7488 2222
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