Greenhouse gas emissions from agriculture in the EU: A spatial assessment of sources and abatement costs

Agriculture contributes significantly to the emissions of greenhouse gases in the EU. By using a farm-type, linear-programming based model of the European agricultural supply, we first assess the initial levels of methane and nitrous oxide emissions at the regional level in the EU. For a range of CO2 prices, we assess the potential abatement that can be achieved through an IPCC-based emission tax in EU agriculture, as well as the resulting optimal mix of emission sources in the total abatement. Further, we show that the spatial variability of the abatement actually achieved at a given carbon price is large, indicating that abatement cost heterogeneity is a fundamental feature in the design of a mitigation policy. We assess the efficiency loss associated with uniform standards relative to an emission tax.Climate change, greenhouse gas emissions, agriculture, methane, nitrous oxide, European Union, marginal abatement costs, Environmental Economics and Policy, Q25, Q15,

A Comprehensive Evaluation of Regression Uncertainty and the Effect of Sample Size on the AHRI-540 Method of Compressor Performance Representation

AHRI-540 is the current standard defining the methods for representing compressor performance data. While this standard is widely used across the industry, multiple factors contribute to inaccuracies in data representation including measurement uncertainty, regression uncertainty, compressor to compressor variation, and operation outside of the normal operating envelope (extrapolation). In addition, the number and location of points in the operating envelop also affects the accuracy of the resulting 10-coefficient polynomial. The measurement uncertainty is well known and can be factored into the data reduction. However, the measurement uncertainty is generally not propagated into the regression uncertainty and hence the overall uncertainty in prediction using the polynomial is not known. This uncertainty also changes according to the number of samples used for developing the polynomial. Â As a first step of the evaluation, a regression uncertainty analysis was conducted using a Monte Carlo simulation method. Results showed that the average uncertainty in mass flow rate prediction can be as high as 4% and that in power prediction can be as high as 5%. The worst case maximum absolute error in predicted mass flow rate across all data sets was 17% and that for power was 9%. Error in predicted power and mass flow rate is higher for larger capacity compressors. For most compressors, the high errors occur in the region of the envelope with low suction and low discharge dew point temperatures. Â A study of sampling considering different sample sizes and multiple sampling methods was conducted. Two additional methods of compressor performance representation were also analyzed. This analysis was presented with several challenges, particularly since the compressor operating envelope is a non-rectangular domain. A sampling method using Latin Hypercube Design (LHS) and a proposed alternative sampling method based on polygonal design of experiments (PDOE) were evaluated. The resulting models were validated against a measured data set of more than 600 points encompassing the operating envelope for each compressor. In general, both the LHS and PDOE methods yielded similar errors in mass flow rate for samples sizes of 12, 14 and 16. Thus, for mass flow rate, it is possible to build a model with 12 systematically selected test points. For power prediction, the average error for the LHS and PDOE methods using AHRI540 and two other methods was lower than 2% for all sample sizes

Neutrino-Dark Sector Equilibration and Primordial Element Abundances

After neutrinos decouple from the photon bath, they can populate a thermal dark sector. If this occurs at a temperature above ~100 keV, this can have measurable impacts on light element abundances. We calculate light element abundances in this scenario, studying the impact from rapid cooling of the Standard Model neutrinos, and from an increase in the number of relativistic degrees of freedom $N_{\rm{eff}}$, which can occur in the presence of a mass threshold. We incorporate these changes in the publicly available BBN code PRIMAT, using the reaction networks from PRIMAT and from the BBN code PArthENoPE, to calculate Y$_{\rm{P}}$ and D/H. We provide limits from the two different reaction networks as well as with expanded errors to include both results. If electron neutrinos significantly participate in the cooling, we find limits down to temperatures as low as 100 keV. If electron neutrinos are weakly participating (for instance if only the mass eigenstate $\nu_3$ equilibrates), cooling places no limits. However, if the dark sector undergoes a "step" in $N_{\rm{eff}}$, there can be additional, $\omega_b$-dependent constraints. These limits can vary from strong (for low values of $\omega_b$) to a mild preference for new physics (for high values of $\omega_b$). Future analyses including upcoming CMB data should improve these limits.Comment: 6+6 page

Performance Analysis of Ejector Cycles for Separate Sensible and Latent Cooling in Air Conditioning

While the overall system efficiency of split air conditioning (AC) systems has improved over the last three decades, residential air handling units (AHUs) used in those systems have essentially stayed the same in size, shape, form, and efficiency. Incremental improvements have been made to AHUs to address safety, functionality, and energy-efficiency concerns, however, their overall structure has remained the same. A promising technology that addresses fundamental challenges with conventional cycle efficiencies are ejector-based cycles, more commonly employed in refrigeration applications, but with great potential in AC systems as well. An ejector employed as an expansion device can recover expansion losses, boost pressure, and facilitate a dual evaporator system. This paper presents four categories of ejector enhanced vapor compression cycles (VCCs) leading to seven potential system concepts: standard two-phase ejector, two variants of condenser outlet split (COS), diffuser outlet split (DOS), and three variants of separator outlet split (SOS). The concepts were investigated via numerical model studies and two promising ejector enhanced cycles for a residential AC application emerged: COS and DOS. The COS and DOS ejector enhanced cycles improved seasonal energy efficiency ratio (SEER) by 4%–8% above a 15 SEER baseline AC system and improved the total coefficient of performance (COP) by 9%–11%. With the COS or DOS ejector enhanced cycles, losses quantified by exergy destruction were reduced by up to 18%

Identification of Mental States and Interpersonal Functioning in Borderline Personality Disorder

Atypical identification of mental states in the self and others has been proposed to underlie interpersonal difficulties in borderline personality disorder (BPD), yet no previous empirical research has directly examined associations between these constructs. We examine 3 mental state identification measures and their associations with experience-sampling measures of interpersonal functioning in participants with BPD relative to a healthy comparison (HC) group. We also included a clinical comparison group diagnosed with avoidant personality disorder (APD) to test the specificity of this constellation of difficulties to BPD. When categorizing blended emotional expressions, the BPD group identified anger at a lower threshold than did the HC and APD groups, but no group differences emerged in the threshold for identifying happiness. These results are consistent with enhanced social threat identification and not general negativity biases in BPD. The Reading the Mind in the Eyes Test (RMET) showed no group differences in general mental state identification abilities. Alexithymia scores were higher in both BPD and APD relative to the HC group, and difficulty identifying one’s own emotions was higher in BPD compared to APD and HC. Within the BPD group, lower RMET scores were associated with lower anger identification thresholds and higher alexithymia scores. Moreover, lower anger identification thresholds, lower RMET scores, and higher alexithymia scores were all associated with greater levels of interpersonal difficulties in daily life. Research linking measures of mental state identification with experience-sampling measures of interpersonal functioning can help clarify the role of mental state identification in BPD symptoms

Integrated Thermal Energy Storage for Cooling Applications

Many commercial and industrial facilities are cooled using vapor compression cycles (VCC). The performance of such systems degrades with high outdoor temperatures causing high peak electric demand increase, reduced efficiency and lower cooling capacity. An Integrated Thermal Energy Storage System (ITESS) utilizing chilled water provides additional subcooling for a VCC condenser, thereby increasing the capacity of the entire system and providing significant reductions in electric demand and consumption. The ITESS uses a dedicated chiller to cool a thermal storage tank, typically at night when electricity demand and rates may be lower. This thermal reservoir is used during the following day to sub-cool refrigerant leaving the condenser. This additional cooling increases the overall cooling capacity of the chiller without increasing the electrical demand. The following paper outlines the results of a demonstration of the ITESS at an industrial facility in Syracuse, NY. The existing 176-ton chiller, which provides cooling for air conditioning a laboratory space and chilled water for compressor testing, was retrofitted with a 33-ton supplemental chiller, 10,000-gallon water tank, four sub-coolers, and two sub-cooler pumps. The ITESS was instrumented with a number of sensors to measure critical parameters to assess its performance. The test results showed that the cooling capacity of the existing chiller increased by 2.2% - 34.2%, depending on operating conditions, with the addition of subcooling. The ITESS increased existing chiller efficiency between 0.6% - 28.5% and has the potential to reduce power demand by 0.7%-34.3%. Total energy consumption for the system was essentially unchanged, increasing on average by approximately 0.05%, well within the margin of error

Comparative Studies of Scroll and Rotary Compressors for US Market Heat Pumps and Air Conditioners

Rotary compressors have long been developed and adopted for heating, ventilation, and air-conditioning (HVAC) applications across Asia, primarily due to their simpler mechanism and fewer parts as compared to their counterparts such as scroll compressors. However, rotary compressors in heat pumps (HPs) and air conditioners (ACs) in the US have limited market share and are often confined to systems smaller than 3.0 tons (10.6 kW). This paper consists of two parts; the first is on rotary compressor technology and its advantages and disadvantages from both technical and market standpoints. The review consists of a survey of the literature, as well as a survey from field experts through anonymous interviews. Conventionally, rotary compressors are regarded as having lower efficiency in systems larger than 3.0 tons (10.6 kW), which limits their current application to small packaged systems and automotive ACs. The second part includes an experimental investigation of compressor and system efficiencies using scroll and rotary compressors. The compressors compared were drop-in replaced in typical 2.5 (8.8-kW) and 5.0-ton (17.6-kW) R410A split HP systems. Experimental tests, both in cooling and heating modes, were conducted under AHRI 210/240 Standard operating conditions. The test units were extensively instrumented on both the refrigerant and air-side to measure temperature, humidity, pressure, flow rate, and power consumption, according to ASHRAE Standard 41.2. Indoor and outdoor units were placed in a wind tunnel and in an environmental chamber, respectively. The results showed the 2.5-ton (8.8-kW) unit rotary compressor’s isentropic efficiency was 2.6% and 14% higher than the scroll compressor in cooling and heating, respectively. At 5.0 tons (17.6 kW), the isentropic efficiency of the rotary compressor was 5.4% lower in cooling and 6.3% higher in heating. In terms of volumetric efficiency, at 2.5 tons (8.8 kW) the rotary compressor was 1.7% lower in cooling than scroll compressor, and comparable to the scroll compressor at two of three heating mode test points. At 5.0 tons (17.6 kW), the rotary compressor volumetric efficiency was 0.7% and 2.8% higher than the scroll compressor in cooling and heating mode, respectively. The overall system with the rotary compressor had 5.7% higher seasonal energy efficiency ratio (SEER) and 3.0% higher heating seasonal performance factor (HSPF) than the scroll compressor at 2.5 tons (8.8 kW). At 5.0 tons (17.6 kW), the system with the rotary compressor was 2.6% higher in SEER and 0.6% higher in HSPF compared to the system with the scroll compressor