Abstracts of Non-refereed Publications
Reiss, E., A.J. Both, and D.R. Mears. 2004. Greenhouse floor heating. ASAE paper No. 04-4040. ASAE, 2950 Niles Road, St. Joseph, MI 49085-9659, USA. 13 pp.
Abstract
Making
use of the synergy of both bottom heat and bottom watering, many greenhouse
growers are utilizing heated ebb and flood floors as their main plant
productions system. While the typical design and control strategies that are
implemented for these systems work well, they still may not be optimized for
energy efficiency or crop benefit.
Accurate and flexible computer models can be extremely valuable design
tools when applied to the study of greenhouse environmental control systems and
can answer many questions without the time and expense associated with
experimental research.
This paper describes the first attempt to develop and verify a model of a
floor heating system that is installed in a research greenhouse located at Cook
College, Rutgers University in New Brunswick, NJ.
This model considers the simple case of a heated ebb and flood floor
without a crop, and will be used to develop more complex models.
The model’s output under predicted the average floor surface
temperature measured in the greenhouse by an average of 3.20°C (5.76°F),
for eight combinations of pipe water temperature and greenhouse air temperature
considered, with a standard deviation of 0.28°C (0.49°F).
By raising the external radiation temperature used as input to the model
by an average of 8.63°C (15.53°F), the models predicted
average surface temperature matched the measured average surface temperatures
for all eight cases considered.
In order to confidently verify the model’s output, a better method for
determining the external radiation environment is necessary.
More complete models need to be developed that include the soil below,
the crop above, and all the thermal relationships that exist between them and
the greenhouse.
With such models, the thermal performance of these systems can be better
understood, and the effects of changing design parameters as well as control
strategies can be determined.
Both, A.J. 2004. Rutgers high tunnel research. Proceedings of the 49th New Jersey Annual Vegetable Growers’ Association Meeting, Borgata Hotel Casino and Spa, Atlantic City, NJ. pp. 83-90.
Abstract
As part of a
project funded by the New Jersey Agricultural Experiment Station and directed by
Drs. Steve Garrison and Wes Kline, six high tunnels were constructed at two
different locations: two of the tunnels were erected on the horticultural
research farm at the Cook College Campus in New Brunswick, NJ. The remaining
four tunnels were installed at the Rutgers Agricultural Research and Extension
Center in Centerton, NJ. The tunnels were constructed according to the Penn
State high tunnel design with some minor modifications. The tunnels will
initially be used for research on the feasibility of season extension for tomato
production.
Both, A.J. 2004. Greenhouse environment control. Proceedings of the 49th New Jersey Annual Vegetable Growers’ Association Meeting, Borgata Hotel Casino and Spa, Atlantic City, NJ. pp. 91-95.
Abstract
Successful
greenhouse crop production requires that growers have good control over the
greenhouse environment. The most important environmental parameters that need to
be controlled include temperature, light, humidity, and the carbon dioxide
concentration. Growers use heating, ventilation, and cooling systems to control
the greenhouse temperature and humidity levels. In addition, supplemental
lighting and shading systems can be used to control light levels. Carbon dioxide
enrichment is used to provide a carbon dioxide concentration high enough as not
to limit photosynthesis. The control of one parameter, e.g., temperature, can
have an impact on the control of other parameters, e.g., humidity and carbon
dioxide. Providing optimal environment control under the constantly changing
weather conditions is a challenging task that can be made easier with a
computerized control system. The discussion in this paper touches on some of the
technologies available to growers to help them control their greenhouse
environment.
Reiss, E., D.R. Mears, and A.J. Both. 2003. Greenhouse floor heating. ASAE paper No. 03-4039. ASAE, 2950 Niles Road, St. Joseph, MI 49085-9659, USA. 14 pp.
Abstract
Floor heating in greenhouses has become increasingly
popular over the past several decades due to the considerable benefits it
provides. Extensive work was done
on earlier versions of warm floor designs to determine their heat transfer
coefficients and thermal masses. Typical floor heating designs of today differ
from those early systems, and have not been researched as thoroughly.
With the goal of quantifying the performance of these modern designs, a
recently constructed open-roof greenhouse was outfitted with a typical heated
ebb and flood floor system, and instrumented to measure the heat input to the
floor as well as other energy flows. A mean heat transfer coefficient from the
floor heating pipes to the growing area was determined to be 5.97 W/m2-K
(1.05 Btu/hr-ft2-°F) and three control strategies were
implemented and evaluated. Effective evaluation of the strategies was found to
be difficult due to very different outdoor environmental conditions that were
present for each control strategy. In
future work the thermal mass of the system will be determined and a model will
be developed for the floor system and verified by data collected.
With such a model different control strategies can be effectively and
quantitatively compared.
Fleisher, D.H., A.J. Both, C. Moraru, L. Logendra, T. Gianfagna, T.C. Lee, H. Janes, and J. Cavazzoni. 2003. Manipulation of tomato fruit quality through temperature perturbations in controlled environments. ASAE paper No. 03-4102. ASAE, 2950 Niles Road, St. Joseph, MI 49085-9659, USA. 9 pp.
Abstract
Quality factors such as size, color, taste, and
nutritional content are important criteria for marketing of greenhouse tomato
fruit. While the majority of the research on fruit quality factors
focuses on effects of post-harvesting and storage conditions, the environmental
conditions during plant growth and the time for which the fruit is allowed to
ripen on the vine also influence fruit quality. Growth chamber experiments were performed with tomato (cv.
Laura) aiming to study the influence of air temperature perturbations during
fruit set on fruit quality at maturity, the time to harvest, and the harvest
window. Plants were grown in 6”
pots and pruned to the 2nd true leaf above the first fruit cluster. Nutrients were provided through a drip irrigation system. All
plants were grown under the same environmental conditions except for a two week
period beginning 10 days after fruit-set during which plants were assigned to
one of three day/night temperature treatments, 28/23°C, 23/18°C, and 18/13°C.
Five tomato fruits were harvested from each plant at three distinct
physiological ages; breaker stage (taken as the point at which 25% of the fruit
begins to turn red), breaker stage plus three days, and breaker stage plus six
days. Harvested fruits were
analyzed for mass, size, color, soluble solids content, pH, acidity, viscosity,
and other quality parameters. Initial results show significant temperature effects on fruit
size, mass, developmental rate, and fruit processing characteristics.
The results are applicable towards the development of more efficient
plant production strategies for greenhouse growers and for NASA’s advanced
life support research program.
Sase,
S., E. Reiss, A.J. Both, and W.J. Roberts. 2002. A natural ventilation model for
open-roof greenhouses. ASAE paper No. 02-4010. ASAE, 2950 Niles Road, St.
Joseph, MI 49085-9659, USA. NJAES Paper No. P-12232-04-02. 9 pp.
Abstract
A computer simulation model for natural ventilation in open-roof greenhouses was developed to predict the ventilation performance. The model predicts ventilation rate and the temperature differences between inside and outside, based on the weather and structural conditions including internal net radiation, wind velocity, and height and area of the roof openings. The ventilation rate was calculated from thermal buoyancy and wind forces. A sensible heat balance was incorporated to calculate the ventilation rate and the temperature difference simultaneously. A four-span open-roof greenhouse with roof sections hinging at the gutters and opening at the ridge, constructed on the Rutgers University campus, was used for data collection. Measurements of climate conditions in the direct vicinity of the greenhouse were conducted. Using the observed outdoor and greenhouse conditions, the model parameters were calibrated statistically. The accuracy of the model and the modifications to the model are discussed by comparing the predicted and observed greenhouse temperatures. It is shown that the internal temperature rise depends on the roof configuration as well as solar radiation and wind velocity. The resulting simulation model can be used to implement new environment control strategies for open-roof greenhouses.
Hsiang
H., S. Kang, A.J. Both, and K.C. Ting. 2001. Analysis tool for food processing
and nutrition (FPN) subsystem in an advanced life support system (ALSS). ASAE
paper No. 01-3020. ASAE, 2950 Niles Road, St. Joseph, MI 49085-9659, USA. NJAES
Paper No. P-70501-12-01. 16 pp.
Abstract
Long-duration space missions require the design of an advanced life support system (ALSS). Four interacting subsystems have been identified within an ALSS: Crew, Biomass Production, Food Processing and Nutrition (FPN) and Waste Processing and Resource Recovery. The main function of a FPN subsystem is to prepare palatable dishes based on pre-determined menu cycles, by using available food ingredients, in order to satisfy the daily crew nutrient requirements. The FPN subsystem will impact the other subsystems in an ALSS while carrying out the necessary food processing activities.
An effort has been made to develop a top-level model of a FPN subsystem to evaluate the feasibility of potential ALSS designs. The FPN model was designed to make use of existing nutritional data, menu cycles, and related food processing information to study the effectiveness of the FPN subsystem within an overall ALSS model. The main performance indicators for a FPN subsystem are the required mass and volume, the amount of ingredient usage, crew time requirements, waste generation, energy consumption, and heat generation from food processing. The developed model is useful for studying “what-if” types of scenarios. The developed FPN model was implemented using the JAVA object-oriented programming platform. Therefore, the model can be executed via the Internet to encourage broad usage.
Kang,
S. and A.J. Both. 2001. A management information system for food nutritional
analysis and biomass production in an advanced life support system. ASAE paper
No. 01-3021. ASAE, 2950 Niles Road, St. Joseph, MI 49085-9659, USA. NJAES Paper
No. P-70501-11-01. 10 pp.
Abstract
A management information system (MIS), including a database management system (DBMS) and a decision support system (DSS), was developed to dynamically analyze changeable nutrient information from biomass production and food preparation. By using the DBMS, the nutrient composition of a 20-day diet for the Advanced Life Support (ALS) program was analyzed, and the optimal level of food mass for the crew’s consumption was calculated. Also, the required size of a biomass production area needed to satisfy the food requirements for the crew was determined.
Both,
A.J., E. Reiss, D.R. Mears, and W.J. Roberts. 2001. Open-roof greenhouse design
with heated ebb and flood floor. ASAE paper No. 01-4058. ASAE, 2950 Niles Road,
St. Joseph, MI 49085-9659, USA. NJAES Paper No. P-03232-15-01. 13 pp.
Abstract
An open-roof greenhouse production system with a heated ebb and flood floor irrigation system is being developed and evaluated. In addition to continuous roof vents, the greenhouse is equipped with sidewall vents to allow for ventilation during windy and rainy conditions. This paper discusses the design details as well as the instrumentation used for the evaluation. Preliminary data, collected over a 2.5-month period, of light and temperature conditions are presented. The greenhouse temperature closely followed outside temperature conditions for the entire measurement period when the inside temperature exceeded the set point. The inside light conditions were significantly affected by the greenhouse structure, and inside light intensities around solar noon could exceed outside light intensities due to reflection from the opened roof segments.
Summary
A long-term research project resulted in the design, construction, and operation of a commercially scaled demonstration greenhouse for hydroponic lettuce production. One full year of production is planned to verify the economic feasibility of the developed growing system. An agricultural cooperative plans to use the demonstration greenhouse as a training facility and license the developed technology to prospective greenhouse growers. The ultimate goal is to create new and exciting opportunities in an emerging high-tech vegetable industry.
Abstract
The trust of this report suggests supplemental lighting design processes that might be used to achieve desired PAR levels and adequate uniformity over a lighted space. Measured PAR distribution patterns from eight commercially available 400 W HPS luminaires are used in three design examples, implemented through a commercially-available lighting design computer program. Results suggest that PAR uniformity within ±10% is achievable at intensities of 200 and 300 μmol-m-2-s-1 in greenhouses and plant growth chambers. When PAR intensity is significantly lower (e.g., 50 μmol-m-2-s-1), uniformity is more difficult to achieve. This study suggests the desirability of developing computer data file standards for PAR, rather than vision lighting, for commercial luminaires, and obtaining a consensus database of surface reflectance values for materials used in plant growth chambers and greenhouses. Results also suggest that luminaire selection can have a significant effect on lighting energy use and operating cost because of different numbers of various models of luminaires required to meet a design goal, not just luminaire-to-luminaire efficacy differences.